Games of Go on Disk (GoGoD) is run by John Fairbairn (until December 2013 jointly with T Mark Hall). Its main product, the GoGoD encyclopedia, has a collection of more than 79,000 game records of pro games, in SGF format. A great resource for every go player.
More than 30000 games in SGF format, from the following events: Chinese-Japanese Super Go, Gosei, Honinbo, International Meijin, International Tengen, Ing Cup, Judan, Kisei, Meijin, NihonKiin, Oza, Pro Best 10, Shusaku, Tengen
Around 50.000 (as of January 2013) game records in SGF format, freely available for download.
Game records in SGF format from the Kisei, Honinbo, Meijin, Judan, Tengen, Chinese-Japanese Super Go, International Meijin and International Tengen tournaments.
Send one of your games to the Go teaching Ladder, and get a review by a stronger player! This is definitely a good way to improve. All the reviews from the past are available from this web site, too, so you could also play through some of them.
Links to game record collections and go database software
Jan van der Steen's site with go news, lots of game records, and other go-related stuff.
"Share SGF games with friends." Also, many professional game records.
Jan van Rongen's site features a huge collection of games of Cho Chikun, a smaller, but growing collection of games by Yamahita Keigo, and a practically complete list of the games in Hikaru No Go. Furthermore, there are several articles on go-related topics.
A go database program, with a pattern search engine, and (in the full version) a huge amount of games: more than 700,000 pro and top ama games. They also have a joseki database, and OCR software for go diagrams.
This is a site with go news, and game records. For members (20$/year), games with commentary by professionals are available.
Last entries seem to be from 2013 - not sure whether the site is still active.