Penn said that he wants to fight for the UFC. IF THE UFC allows him to fight outside of the UFC as well. Funny how he decided to do this after he won the belt.
Penn also said that he only wanted to defend his UFC Welterweight Title only once a year. ( I Don't know if he was joking around when he said this though)
Penn also said after beating Hughes, Penn wanted the same amount of money Hughes was getting. He was also going to hold out for more money.
Pretty much I think that Penn knew all along that if he wins a belt in the UFC and as long as he has the belt, he can't fight outside of the UFC. Seems like if you are a UFC fighter that doesn't have a belt, then you can fight outside of the UFC.