I ordered this chip this evening.
I am trying to control my dcr-sr200. It's a digital video camera (hard disk based). I want to be able to perform time lapse operations with it. this little chip (http://www.elmelectronics.com/DSheets/ELM624DS.pdf) takes care of the trivial matters of letting the computer speak to the camera. I'm hoping to let Arduino do the talking, though.
I will report back after I am done wiring this chip up and report my results for anyone who cares, or the random googler.