Once cameras started becoming popular, it was clear that there will be many innovative uses of camera phones. For one obvious thing, these cameras could be used to read special symbols — like special kind of ‘bar codes’ — that could be used for marketing, inventory control, and location based services. In fact, a camera equipped phone on internet is a very powerful information gadget indeed.
The developments have been slower than I anticipated due primarily to complexities in visual processing. First generation companies seem to be coming in market now. Stefanie Olsen has a good report on this in News.com.