iPhone: The iPhone has a pretty decent camera for casual snaps, but it can be difficult to operate if you're wearing gloves or don't want to get chicken grease on the screen. Soundsnap lets you use any sound to trigger the camera, making remote operation possible.
There's not much more to the app than that, though you can adjust the sensitivity to make sure it isn't randomly set off by every passing stranger. As Nick over at Gizmodo notes, if you have a Bluetooth headset, you can get full remote operation, which could be useful with a tripod or other mounting system. (Nick took the sample picture you can see here to prove the Aussie-developed app works, which also serves as a reminder that I haven't yet finished decorating the Lifehacker cubicle, though it is more "finished" than it was and is hands-down the tidiest in the tech division).
Soundsnap is a $1.19 download for iPhone.