If you've got both a (Canon or Nikon) DSLR camera and an iPhone (or an iPod Touch), then start getting the two to play nice. Plenty of folks already hook their DSLRs up to their laptops to keep an eye on things, and using your iPhone as a remote instead would give you a bit of freedom.
The DSLR Camera Remote by onOne lets you do more than just trigger pictures — you can also adjust your shutter speed, aperture and other settings, and stream the camera's view right to your phone. onOne just released a new version of the software that updates it look and adds supported Nikon cameras to the Canons it already accommodated. If you've got any other kind of DSLR, you're probably going to have to wait a bit.
Here's a video of the iPhone DSLR Remote in action: