i will let you know about it, but the game will come out in the end of may here in europe...
anyway:
smash bros brawl is the third game in the series. (smash bros64 on the n64, smash bros melee on the gamecube and now smash bros brawl on the wii)
its a non-gory 4-player-fighting game. the characters are nintendo-characters (as a first in the series, brawl also features 2 non-nintendo-characters) like mario, kirby, link, zelda etc., the stages are funny and colorful, and you just bash on each other until someone falls down the level (every stage is designed so you can fall down on each sides, or be shot up to the sky)
half of the fun of the game lies in the feature of items, which make the battles kinda random. you can pick up hammers, poke-balls and other random stuff and beat the crap out of your opponents.
its nothing like street fighter, guilty gear or mortal kombat, which are classic 1 on 1-fighting-games. its just like a party-version of fighting-games. max out your fun by playing with 3 friends
check out this video for a quick impression: