Yes, this is the new SSB game for the Wii, but it will not be a launch title (it will be out in 2007). This is the site for the new .
They are adding (of course) new characters, and some third parties are joining in.

Araq: Fixed your hyperlink.

I wonder if when Snake gets knocked off the arena if we hear the Colonel, or another character, go "Snake? Snake? SNAKKKKKKKKEEEEEEEEEEEE!!!!"

Other predictions. Raiden will be in as a character who is identical to Snake, but slightly weaker and faster.

We are all expecting that to happen, tell the truth now...

Oh, the graphics are awesome! And Wario is now with the bunch!
This is going to be a bitchn' game!

I'd think it be funny if snake put suitless samus in a hold:
Snake: Where's the Metal Gear?
Samus: I don't know, let me go NOW...
Snake: Alright, where's your gun?
Samus: Who says I have a... HEY, STOP GROPING ME!
(Then we see Snake get thrown of the edge.)

Let's see here, now, and assess the situation. Kojima has given the rights for Snake for this game, and I'm assuming Liquid will be there too. I hope to god Raiden won't be there, but I'm praying to god Gray Fox will be. However, I can't help but think they won't sign on a couple of their other characters as well...like someone from Zone of the Enders or that Boktai dude. Now, it's a commonly known fact that Kojima Productions is owned by the larger company, Konami. And what other franchises do they own? Well, for one, bomberman, another character that would fit in Brawl well. However, they also currently (I think) own the rights to the Teenage Mutant Ninja Turtles...I hope they stay right where they are with Raiden and the other rejects. BUT, Konami does happen to own the Castlevania franchise. Just imagine Alucard, one of the Belmonts, or (dare I say it...), Dracula himself appearing in the game. I wouldn't doubt it, either, due to their recent friendship with Nintendo (seems like those DS Castlevania games are multiplying like rabbits). However, all of this is really just speculation on my part.
Now, I reallize that there is less than 1% of a percent, that this will happen, but I wish Bungie would sign the Chief on. But, again, this is just wishfull thinking...a more realistic character idea would be Leon or Ada Wong from RE.
Also, I have some ideas of other Nintendo characters I'd like to see. For one, that guy from Geist. He needs a chance to redeem himself. Second, I think that Shy Guys need a place as well. And finally, Geno or Mallow from the BEST SNES GAME OF ALL TIME, Super Mario RPG.
Thanks for valuing my input.

Who the hell is Raiden?

He's this gay dude. He's like the mentally challenged, illegitamate bastard son of Snake and Gray Fox (ok, not really, but he might as well be...and yes, I know that it snake wouldn't be able to get fox pregnant, but if he could...never mind....)

.... I wouldn't count on there being more than two MG characters, and also I'd be surprised if they featured any more than very few more Konami characters. You're naming enough to fill a whole Beat-Em-Up.

Ah. I see. Does the character just say stupid stuff or ddo stupid stuff?