Stanford Fleet Street Singers
Carleton Knights (They don't have a web page)
Goucher Red Hot Blue
Loyala College Chimes
http://www.singers.com, also known as Primarily A Cappella. They have a catalog, a reasoning for the true spelling of "A Cappella", and some other cool stuff.
http://www.casa.org, the Contemporary A cappella Society of America. For a small fee ($15 or $30) they'll send you arrangements and whatnot. Check it out.