
And one of these? (iPOD)

And, of course, a computer.
Then you need this:

It turns your iPOD into a remote for your camera. And it really works. A much cheaper alternative to the Nikon wireless remote, especially since I already had the DSLR and iPOD.
Check it out here.
The only real drawback is that the camera has to be tethered to a computer with wireless hardware. Which really isn't too much of a big deal since the camera needs to be on a tripod for this to work, very well anyway. Hmmmm, one more use for a nice, tiny netbook....
