XML is one of those aspects of websites everyone uses, but few understand. We've gathered 20+ tools to help you with just that.
Altova.com - A commercial company offering a full suite of XML editing tools.
CafeConLeche.org - Numerous resources, current news, recommended reading list and more.
Don't Invent XML Languages - Though XML is easily customizable, this site tells you why it's better to stay with one of the main five versions.
eXist - An open source XML database.
Flash & XML FAQ - A FAQ about the interactions between Flash and XML.
JiBX - A framework for binding Java objects with XML.
Open XML Editor - A free XML editor with form testing and validating.
STG XML Validation Form - A free validator for your XML documents.
Tizag XML Tutorials - Tutorials for just about every aspect of XML.
TopXML - Has tutorials and quizzes for the beginner in XML.
Vex - A visual editor for XML that provides you with a word processor-style interface.
W3C Standards - This website specifies the official syntax for XML.
XML and Databases - A guide to using XML as a data storage system.
XML Checker and Validator - Checks your XML document both for form and validation.
XML Cooktop - A free XML editor for Windows.
XML Copy Editor - A free XML copy editor with built-in validation.
XML Developer Center - Contains downloads, tutorials, a community and more.
XMLFiles.com - Features tutorials, samples, links and more.
XMLmind XML Editor - Offers both free and paid versions with the paid version offering more features.
XML Schema Tutorials -Tutorials for all skill levels from W3Schools.
XML.com - Full of articles and introductions to all aspects of XML. (via)