Solid resource
http://www.websteruniv.edu/~barrettb/achebe.htm
on Achebe's novel, including information on the author and the background. Includes audio of a discussion of the novel.
Excellent resource
http://www.unc.edu/~hhalpin/ThingsFallApart/index.html
on the novel, with a wide range of other resources, including an art and culture gallery and a listing of some of the proverbs in the novel.
Large resource
http://www.postcolonialweb.org/achebe/achebeov.html
put together largely by university students. Includes general information on Achebe and links to information on other post-colonial African literature.