Douglas Adams had a revelation one day and that revalation evolved into HHGTTG which has been (and still is I guess) a Book, a Radio Show, A TV Show, not to mention a series of sequels & short stories, even a video game...
Join Earthman Arthur Dent, & Ford Prefect his pal from Betelgeuse on their quest to update the Guide and generally stay alive in a very odd very dangerous universe. They get "help" from Zaphond beeblebrox, the 3 armed 2 headed president of the galaxy and inventor of the Pan galactic Gargle Blaster, along with Trillian (the brilliant Earth Girl with pet mice) Marvin the Paranoid Android and the most useful creature in the universe - the Babel Fish.
Meanwhile, back here on earth you can check out some HHGTTG links!
You might want to check out the official BBC Hitchhikers site first. -thanks for pointing it out Garvice
H2G2 is the Earthbound attempt an emulating the amazing guide & is chock full of lots of strange info.
Jupiters Red Spot has a whole lot of HHGTTG Links
There's even a Douglas Adams News Group where you can catch up on the latest news & gossip about the creator and his current projects.
If you are an SFFN fan & have more HHGTTG sites you would like listed here, let me know! I'd like to have a list of fan recconmended sites here!