Kwame, Javaris Crittenton, and 1st round picks in 2008 and 2010 go back to the Grizzlies according to the Memphis Commercial Appeal. I thought the Lakers played a little bit over their heads so far and didn't consider them a legitimate title contender, but that changes now. Andrew Bynum is still out at least a month, but Gasol will more than make up for his absence now. When Bynum comes back, the Lakers will have a tremendous low post game, and the best scorer in the league in Kobe. They will be able to have a great high/low game that will only make Kobe better.
Gasol's name has been brought up continuously over the last 2 years in trade talks, especially with the Bulls. I don't recall hearing any Lakers interest in him. This is a very surprising trade.
Why would the Grizzlies want Kwame Brown? They don't. Making trades in the NBA is a bitch because you have to be able to match contracts. Kwame is a free agent at the end of the season, so they won't have to deal with his ridiculous contract next year. Javaris Crittenton is somebody I really like and hasn't gotten the chance to show what he can do in Los Angeles behind Jordan Farmar and company. He's a talented rookie point guard, and his size also makes it possible to play the 2. However, he's not going to beat out Mike Conley at Point Guard anytime soon. Getting the 2 first rounders back was the key to the deal for the Grizz, but those picks are likely going to be towards the end of the first round now with the Lakers being a formidable force in the Western Conference.

Update...
Mike Bresnahan of the LA Times:

The Lakers are also expected to send Marc Gasol, one of their 2007 second round draft picks and Pau's brother, to the Grizzlies. Separately, the Lakers are expected resign guard Aaron McKie and send him to the Grizzlies to help make the salaries match up. McKie played 10 games for the Lakers last season.

That's hilarious.