Activision's announced a PSP version of Wild West shooter GUN.
It's being developed by Rebellion (cor, they get around a bit don't they?) in conjunction with original scribes Neversoft, and should be out this autumn.
In it, players take on the role of Cotton White, a gunslinger six-shooting his way around the late-1800s Wild West, taking on all of the stuff from the recent console versions as well as new side-missions, quick-play modes and multiplayer. There's also talk of new gameplay features, although we've yet to hear what those are.