WorthPlaying written up a short preview of Activision and Raven's upcoming PSP version of X-Men Legends II: Rise of Apocalypse. Here's a bit to start you off:
Raven Software was evasive on the subject of what the other comic book missions were, since they said that the titles would reveal the identity of certain PSP-exclusive characters that they'd like to see remain exclusive. They did confirm that X-Man would be playable in this build of the game, though, which in turn confirms that at least one mission based on the best-selling Age of Apocalypse alternate reality storyline has been added to the PSP game. This suggests that possibly one or both of the other remaining hidden characters exclusive to the PSP could be from Age of Apocalypse, although Raven Software refused to confirm any of our guesses. They would only say that one of them was a character frequently requested by fans, whose powers they had to "tone down a bit" for the US release. Your guess is as good as ours, folks.