Jason Perkins of www.fightline.com has the news:

UFC 87 will go a long way towards determining BJ Penn's future opponents. Penn recently told Fighters Club TV that he is set to move up to 170 to face the winner of UFC 87's Georges St. Pierre vs. Jon Fitch contest. The fight, contingent on the health of the victor, will take place at the UFC's annual New Year's Eve card this December 27th in Las Vegas.

Penn also plans to retain his lightweight title and will likely face the winner of Kenny Florian vs. Roger Huerta, which also takes place at UFC 87, at a later date.

Penn also left open the option of moving up to middleweight after cleaning out the light and welterweight divisions.

I'm all for the best fighter's fighting one another.  However, I'm also not a fan of fighter's moving between weight classes...especially if they are the champ.  It just causes alot of problems as far as stability/rankings within weight divisions.  If Penn were to beat the winner of Fitch/GSP...he would then be the champion of two weight divisions at the same time...ala Dan Henderson in PRIDE.  I would like to see Penn fight the winner of Huerta/Florian first, and if he won that fight...then relinquish the LW belt to move up and challenge GSP/Fitch.  Until then...let's see how this story unfolds.