Extensible Stylesheet Language (XSL) Version 1.1: XSL is a language for expressing stylesheets. It consists of two parts: a language for transforming XML documents, and an XML vocabulary for specifying formatting semantics. (W3C Recommendation 05 December 2006

mozdev.org: Hosts a large number of development projects for Mozilla applications

The Annotated XML Specification (version 1.0): Tim Bray, one of the authors of the XML specification, presents this annotated version to make the complicated jargon slightly easier to understand

W3C : Extensible Stylesheet Language (XSL): XSL information at W3C : this page is the starting point to all the official W3C documents about XSL

W3C: XML Query: Home of the W3C's XML Query working group, whose work includes XQuery and XPath

XForms: Repository for this next generation of Web forms, including implementations, mailing lists, working group, and relationship with other W3C work. (W3C Document Formats domain

XML Linking and Addressing Languages (XPath, XPointer, XLink): Contains references and description including an exhaustive bibliography, contact addresses for vendors and service providers, software descriptions, mailing lists, information on user groups, descriptions of projects and case studies. (Robin Cover / OASIS

XML Schema Best Practices: A detailed set of best practices compiled by Roger Costello from discussions among XML Schema experts

XML.com: Information, articles, and services from Seybold Publications and Songline Studios (O'Reilly and Associates). Resource guide includes links to W3C and related developments, drafts, and recommendations