30 Boxes - 30 Boxes is a nice online calendar with integrated maps, multiple themes, weather, blog tracker, instant photo sharing, and much more. You can add feeds, create a profile page and have your buddy list. The service is quite unique and scores above most online calendars available today.
Airset - Create group calendars along with shared contacts, blogs, lists, and files with this tool.
Annomate - Annomate is an online personal organizer with features like calendars, contact management, photo albums, file storage, chat room, and more. Price starts at $3.95 per month.
Anywr - Anywr is a service that lets you import your contact addresses from Outlook and other email accounts to one central place. It also provides an online calendar that you can synchronize with your mobile phone.
AOL Calendar - AOL Calendar comes with your AOL inbox with features such as email drag & drop into calendar to create events.
Assign-A-Day - This is an online calendar for use by teachers and students. Teachers can create a calendar and add assignments for students to view.
Backpack Calendar - Backpack allows you to make pages with to-do lists, notes, files, and images. Backpack also has calendar and reminder features that can be accessed on email or on your cell phone. The calendar feature doesn't come with the free edition though.
BlueTie - This is an email, calendar, and file sharing solution that you can use for your small business on your domain. The free version can have up to 20 users.
BusinesITOnline - BusinessITOnline provides tools for small business including file sharing, invoicing tools, contacts management, and an online calendar. There is a free and premium version of the calendar service.
CalendarHub - This is an Ajax-based online calendar with a drag & drop interface.
CollectiveX - Create sites for your groups with CollectiveX. Features offered include calendars, file & photo galleries, and more.
Cozi - Shared calendar service for families. You can synchronize your Cozi calendars with Outlook calendars.
eloops - eloops is an online project management software complete with calendar, data backup, and social networking software for organizations. Pricing starts from $24.88 per month.
Google Calendar - Google Calendar is another popular online calendar that you can access with your Google account. You can create private or public calendars, merge calendars, and create reminders. If you are using Gmail as your email account, you can open Google Calendar from the link above your Gmail inbox. Quite convenient.
Goowy - Goowy is a flash-based service offering email, online calendar, file storage, IMs with appealing screen visuals. If you like Yourminis start-up page, then you might want to try this out. It comes from the same company. The calendar service is in beta though.
HipCal - A basic calendar service that you can used to set reminders on your phone.
iCal - The popular iCal for Mac can be published online and shared with friends and family.
ifreebusy - This service allows you to upload your calendar and convert between to formats.
Inbox.com Calendar - Calendar service from Inbox.com, the site that offers 5GB email, photo album, and notes.
iZeit - This is an online PHP calendar and to-do list. Multiple users can set their own log-in, password and customizations.
Jotlet - Jotlet provides calendar functionality for your business requirements complete with reporting tools and appointment booking.
Kiko - Another cool calendar with drag & drop feature and many more.
Live Calendar - This is the online version of the Outlook calendar and comes with your Windows Live Hotmail account.
localendar - Create colorful calendars to add to your website.
Luvup - You can create your own social calendar among your friends circle and keep track of common events.
MarkThisDate - Directory where you can share your public calendars.
MyGoya - You can use this online operating system to upload your calendars, documents, bookmarks, and other files on the web.
MyHomePoint - Create a calendar for your family with this tool. You can create private and shared task lists, create reminders for birthdays and family gatherings, and also divide the household chores among your family members
MyMemorizer - This is an basic online calendar with reminder service on the email or mobile phone.
MynoteIT - With MynoteIT, you can create notes accessible from your mobile phone, manage bookmarks and contact lists, and create an online calendar.
Nexo - Nexo allows you to create a group calendar, pictures, videos, tasks, polls, blogs, files and more.
Officezilla - A free web based office suite with calendars, contact managers, message forums, email reader, link sharing, chat, to-do list manager, and more.
Ovosuite - Ovosuite is a comprehensive online suite with calendar features for organizations.
Planzo - Ajax-based new calendar service. You can embed pictures on your calendar background.
Plaxo - You can use the Plaxo calendar to sync with your other calendars.
Reminder Firefox - This Firefox addon is a to-do list manager that you can use to remember important tasks and events. You can import lists from othe calendars and share lists using a FTP or Webdev server.
RSSCalendar - Provides a bare-bone calendar feature from which you can create RSS feeds for your readers.
Scrybe - Cool online calendar with offline synchronization features. Many neat features introduced such as world clock, expanding day boxes, etc. Currently in private beta. Looks promising.
SnapPages Calendar - Another innovative calendar with funky buttons and cool layout. You can also password-protect your events.
Spongecell - Create interactive calendars for your sites or blogs with Spongecell widgets.
SynapseLife - This is a cool one. SynapseLife offers web based contacts manager, calendar, lists, bookmarks, and feeds. All the applications are accessible from any mobile device or cell phone.
Teamspace - Team space is an online office suite for organizations with features such as file sharing, project management, chat, and calendar, among others. The calendar feature has individual time zones, password protection and Outlook synchronization for organizations. Prices starts at $4.99 per member, excluding disk space.
Tilika - Create your events calendar with Tilika and have it send invitations to your friends and monitor who's coming.
Todoist - Todoist is an online task manager with an inbuilt calendar.
Trumba - This is a web-hosted software for publishing website calendars and other event widgets that you can embed into your own website. Subscription costs $99.95 per month
Yahoo! Calendar - This one is Yahoo's offering for organizing your events and appointments. Has to do lists and weather information modules. It can integrate with Microsoft Outlook and Palm devices.
Zimbra Calendar - This is a feature-rich Ajax-based web calendar with features like fast switching between multiple time views, drag and drop event modules, rich text meeting note composer, attachments to meeting modules, reminders, calendar sharing, etc.
Zoho Planner - You can create your to do lists and set reminders for your appointments with Zoho Planner. You can set your pages to private or share them publicly.
Better GCal - Firefox addon for Google Calendar. Creates collapsible header and sidebar, event title text wrap, colored weekend days, week numbers, and skins.
CalendarsQuick - You can create personalized and printable calendar templates with this service.
CommonLoop - This tool is supposed to extract event information from your emails and websites and add them to your calendars. Currently it is in alpha testing.
Calgoo - Calgoo synchronizes your Google, Outlook, and iCal calendars online and offline, and also creates mash-ups of your calendars, schedules and contacts.
Free Online PDF Calendar - Create downloadable calendar templates on PDFs of various size.
Google Calendar Add - You can use this to add contacts from your address book to Google Calendar.
Google Calendar Notifier - This is a Firefox addon to view your Google Calendar events for the day on your browser.
GooSync - Synchronize your Google Calendar with your mobile phone or PDA with this tool.
iCal Exchange - You can publish your iCals on this site for free.
iCal to Google Calendar Import - Import tool for the MACs to send iCal data to Google Calendar.
Memotoo - You can view and sync your personal data like bookmarks, contact details, and calendar online with Memotoo. The free version is limited to only 40 events in a calendar though.
Provider for Google Calendar - You can use this extension for Sunbird, Lightning, and Thunderbird to read and write events to your Google Calendar.
Remember The Milk - A popular to-do list manager that you can use to set list and share your tasks and set reminders. It integrates well with Google Calendar.
Spanning Sync - You can use this to synchronize your Google Calendar and Apple iCal.
Timeanddate - Create calendar templates for any year with public holidays of any country.
Twittercal - Use this to add events to your Google Calendar from your Twitter account.
Webical - A tool that lets you view and edit multiple iCals.
Zyb - A new service that you can use to import your mobile phone contacts, calendar, and messages online. (via)