Microsoft's Camera Phone Search Project and Other Camera Phone Search Tech from ResourceShelf covers a new Microsoft Research project allowing you to take pictures of things in order to get search results back about it.
Snap something with your camera phone, then that goes into an image search database, which identifies the object or type of object in order to run other types of searches about it. Or that's the idea. You can't try it yet, and Microsoft isn't even certain what they may do with it.
How about searching by taking pictures of bar codes? Completely different idea than this project, but thanks for asking! The ResourceShelf post gives you resources on the whole Amazon bar code searching in Japan thing, for the curious. And Frucall, mentioned yesterday by Brian, deals with bar code searching as well. The downside is you have to key in the numbers.