xchords.sourceforge.net in Development \ Misc. Dev. Tools
XChords is utility for converting XML guitar chord definitions to SVG (Scalable Vector Graphics) images and then further to JPEG/PNG/TIFF/PDF documents. Project includes XML Schema and/or DTD. It uses XSLT as the main engine (XSLT->SVG)
XSong represents the song (Lyrics, chords, info, tabs) in XML. In cooperation with project XChords it's able to produce nice looking, printable sheet with song. You can use it to produce also whole song book (in one command). XSong 1.0 License - GNU Library or Lesser General Public License...