• Online Go Server (OGS): Beautiful and easy to use service for playing games online.
• Go problems: Free Java based Go problems for all skill levels with animated solutions.
• Eidogo: Great interactive resource for learning joseki (opening moves).
• American Go Association: The official national organization of American go players. Provides many additional resources, including a free e-journal, information about tournaments, and a centralized U.S. ranking system.
• Sensei’s Library: A repository containing up to date Go-related information and forums.