The photoduino shield looks fun, but the board has to be shipped from Spain and all the components bought individually. It would be cool if SparkFun sold this as a kit.
http://code.google.com/p/photoduino/
“Photoduino is an open source electronic controller for cameras based on the Arduino platform. Its main purpose is to serve as technical support for taking photographs of various techniques such as: Timelapse, High Speed Photography, Photography of insects and animals, or storms Photography HDR Photography among others.”