Marvel.Com The creators and publishers of The Fantastic Four
The Official Movie Site Trailers, videos, info... personally I'm addicted to the little game on there.
Marv Wolfman.Com A fairly small site from the one-time writer of the FF.
Steve Englehart.Com A better site, this - contains a fair bit on his disatisfaction with editorial policy.
The Official Homepage of Mike Wieringo The main artist behind the Mark Waid era, Wieringo drew over 20 issues from 2003-2005, as well as nine additional covers and the artwork to the final issue of volume two. This is his personal site.
FFPlaza The finest FF resource on the web.
The Fantastic Four Fluxion A guide to the third volume of the comic, this is a superbly designed site.
The Fantastic Four Adventure Trail No longer actively maintained, I still visit this one for its amusing "12 Worst FF Issues" feature.
Comic Book Resources Columns, previews, sales...
Fred Hembeck's Official Site Fred's a humourist who was behind Fantastic Four Roast, amongst others. He also gave me a very nice write-up.
Christopher Priest's Official Site Priest was behind the most critically popular period of Luke Cage under the name Jim Owsley. To cite him as the first black Editor-In-Chief in mainstream comics is to do him a disservice: he's so much more than that, as his website goes to prove...