While the free X-Men Origins: Wolverine Feral Senses application for the iPhone is little more than a marketing tool for the console game, its image recognition feature definitely has potential.
The free application, now available via iTunes, has users unlock various bits of exclusive game content by using their iPhone camera to photograph icons that can be found scattered about both the internet and the real world. Find on icon on say, the back of the game box. Photograph it with the application. Once the icon is recognised, exclusive Wolverine content is unlocked. Activision claims this is the first time photo recognition technology has been used in the video game industry, though it's similar to what Ubisoft did with Assassin's Creed 2, or Eye of Judgment's card recognition.
It's all marketing in this case, but I think photo recognition is a technology that could add a nice chunk of interactivity to video games. The iPhone and now the DSi both have built-in cameras and are portable enough, and I'd definitely welcome any game that required me to go outside and reacquaint myself with Mr. Sunshine.