Active Tags: A language for XML native programming, where usual procedure-oriented sentences can be mixed with declarative sentences.
CDuce: A typed, functional programming language adapted to the manipulation of XML documents.
MSDN: XML in Office Developer Portal: Microsoft site offering articles, SDKs, reference documentation, downloads, and webcasts about working with XML in MS Office.
SAX: Official website for SAX, the Simple API for XML, project resources include archived mailing lists, SAX evolution and a download area.
XML Sapiens: A descriptive language for user interfaces of CMS-based web sites.
XML-RPC: A specification and a set of implementations that allow software running on disparate operating systems, running in different environments to make procedure calls via HTTP and XML.