Gosu's main website is libgosu.org. The source code, wiki, issue tracker and change log are all hosted on GitHub
The best entry point into Gosu's documentation is the wiki home page. Try doing the tutorial there if you don't know how to get started, or look at one of the games in the Gosu Showcase board.
Gosu is licensed under the MIT license. Feel invited to fork, port and transmogrify all parts of it!
Complaints, questions, feedback?
- Visit the boards
- Try your luck in the (mostly idle) IRC channel
- Or email me :)