The Official Website of Kurt Vonnegut
Includes a biography, news, book order form, T-shirts, and more.
Kurt Vonnegut: His Life and Work
Includes a complete collection of his works, including commencement addresses. Also has an archives section, for links to "Vonnegut writings from forgotten places."
Vonnegut/Kilgore Trout
http://www.vonnegutweb.com/vonnegutia/trout/index.html
A complete list of all Trout's works, a biography of the character, and descriptions of his appearances in different Vonnegut works. Helpful if you're having trouble keeping track of all his works mentioned in Breakfast of Champions!