Jan van der Steen has a much more extensive collection, but that is password protected and copyrighted. The games here are in the public domain.
(I collected them from many sources, mostly from the net. Martin Müller's collection of games was a good start, and Jan van Rongen had a few more recent games. Also ftp.nuri.net/Go has a lot of stuff, unfortunately mostly of low quality. Many other references contribute a handful of games. Many games have several sources, and where there were contradictions, I have attempted to decide which source was most reliable. Many minor details were corrected. The format has been made a bit more uniform. In particular, all dates are given in ISO standard form.)
Additions and corrections are welcome. Mail to aeb@cwi.nl.