XML

DbcDOM
XML library for DATABUS language. There are basic functions for export/import XML files. Includes additional classes for LinkedLists, Stacks, and Exceptions.
http://dbcdom.sourceforge.net/

Natix
Native XML database for Linux.
http://www.dataexmachina.de/natix.html

XML and Databases
Discusses the relationship between XML and databases. Describes some of the types of software available to process XML documents with databases.
http://www.rpbourret.com/xml/XMLAndDatabases.htm