This has every Super Smash Bros. Melee site you could think of and information on the sites. I haven't found that many just on SSBM so if you know ones I can put on e-mail me.
Nintendo At E3
Has info, lots of screenshots for Super Smash Bros. Melee.
Official SSBM Site
Terrible. It only has some Smash Mail thing.
Other SSBM Sites
Super Smash Bros. Melee World
Great site! Has info on characters, play modes, attacks, etc.