Advances in Camera technology has allowed the mounting of some of these new light weight camera's to even the smallest of RC Models. Film and Digital cameras are now available with a wide range of options such as auto focus allowing for great unique shots from rc models.
In the above links you will find some ideas on how too set up a camera or video unit on rc airplanes and rc helicopters as well as info on which ones have been successfully used by others.
When taking pictures with a rc model be sure you keep safety in mind and do not fly in un safe area's.