At the game's UK launch event, Craig Fairbrass, the voice actor for Ghost in Modern Warfare 2, said the character will get a spinoff comic and possibly a game of his own, although what exactly is not clear.
Here's the quote, which That VideoGame Blog attributes to audio of the event:
I did in the last game a voice for a character called Gaz and in this game I'm now voicing a guy called Ghost, who now just got a spin-off comic of his own and they're talking about another little game to go with it. So, I'm quite excited about it. It's grown and grown and grown.
Destructoid notes the context in which this was mentioned - "another little game to go with" a spinoff comic - means it could be just a flash game to coincide with the book's launch (which coincided with the game's Nov. 10 release). That's a pretty reasonable take, although I've asked Robert Bowling if he or Infinity Ward would like to say any more. Modern Warfare 2's Ghost Getting His Own Game? [That VideoGame Blog via Destructoid]