Presentation of Composers of Midi Music - a very nice site with musics from composers of many places around the world. 

Midi Farm - free midi files.  

The Progressive Rock Web Site - the place to get information about progresssive rock, with many links. Very complete.  

Harmony Central - midi tools and resources.  

World Wide Music - over 300.000 30 sec. audio samples. Must to register, but it's free.  

The Internet Music Pages - information about a wide range of subjects related with music and music making in the Internet.  

Oldfield Music Samples - midi files from Mike Oldfields' musics.  

Peter Gabriel - PG's official site.  

MIDI Composers' Exchange - a place for share music and ideas.

Classical Midi Archives - midi files from many classical composers.