Fuseki Info
Online professional Go games database (more than 35,000 games). Contains game records, game lists, fuseki and joseki trees.
Games of Go on Disk
A collection of around 10000 games distributed on disks.
Go4Go.net
Go game collection of professional game records with a search engine. An English version that runs independently of the go4go.net main site in Chinese.
Professional Games in Smart Go Format
A collection of .SGF format games available for download and study. (quite old)
Stonetalk
Mailing list devoted to the analysis of professional go games.