Go Links

Best tool to learn Fuseki with lessons on basics, and 16 most common fuseki including the Shusaku Fuseki, Cosmic Style, Nirensen, Kobayashi Style, Chinese Fuseki, etc.
Currently one of the strongest go playing engines. Available for PC, iPhone and iPad.
eGo
by Bruce Wilcox. It plays with nine different personalities.
Over 10,000 professional games and 2000 Go problems in your pocket. Can also be used to record your own games.