the coolest app I've seen for the iphone is called iRa. It allows you to view and control surveillance cameras. You can go from camera to camera, control the camera's movements with finger gestures, and take snapshots of what the camera sees.
It's also expensive as hell. Another website posted it would cost 500 bucks.
http://www.lextechlabs.com/2008/07/1...-preview-video