One of the developers behind the Yahoo Purple Pedals project posted a lot of details about how they went about developing a networked bike that automatically uploads geocoded photos to Flickr.
The team created background applications for the GPS-enabled Nokia N95. The software forces the camera to take photos regularly without user interaction and posts the photo, the device’s IMEI ID and the current location to a server application over HTTP. Finally, the server application matches the IMEI to a Flickr ID in its database and posts the photo to Flickr for the world to see.
Both the device-side and server-side applications have been made available under the LGPL license, which should give you a pretty significant head start with developing your own mobile-photo project.