Some other English-language Go sites are listed here.
UK Go Challenge for schools
Neil Moffatt's Learn Go site
Steve Bailey's Go pages
Mick Reiss's Computer Go site
Harry Fearnley's Go siteIncludes his bestiary of remarkable positions.
Tim Hunt's "Milton Keynes Go board"
Peter Wendes's Go teaching site
Tony Atkins' Go teaching site
Matthew Macfadyen's Go tutorials
Henry Segerman's three-dimensional diamond-lattice Go boards
Thomas Wolf's GoTools Tsume Go program.
A web interface to Thomas Wolf's GoTools. It solves simple problems in seconds.
Colin Adams' pagesMore here about Shogi, in its various forms, than about Go.