Interfacing an Arduino Duem with an RCA-output Cam

I just bought a sparkfun microSD storage shield for the arduino. I figured that it might be fun to use an old infrared-visible spectrum camera and log the video feed. The RCA output is the obstacle. I have no idea how to interface it with the arduino. Is someone familiar with RCA signals? Can someone help? Thanks in advance! :)

Oh, Ok. Looks like it's time to find something faster. Maybe I could make something that'll step down the frequency...

BUT: what if I made a standalone 20MHz ardie? or an overclocked ardie? Could that handle it?

Before going into overclocking, research what frequencies are needed. 16MHz or 20MHz make no real difference if need to sample at 13-15 MHz to process the image. With 1 or 2 instruction per sample you ain't going far. You need a processor which is a few orders of magnitudes faster or hardware dedicated to handle video frames.