Amazon has a couple of generic wireless remotes for Nikon and Canon shooters for $3-$6 shipped.
The above Canon remote is a generic replacement for the Canon RC-6, which triggers the Canon Rebel series cameras and the 5D Mark II, 7D, 60D and so on. The price? How about $2.88 with $0.50 shipping.
About the same deal for Nikon in the above remote for $5.95 with free shipping. It’s compatible with the D90, D7000, D5100, etc.
I ordered one of each. I already own a Canon remote, but for $3 it’ll be worth checking out and keeping a spare in my camera bag. And, I don’t even own a Nikon camera right now; however, I use them often enough that it’ll be worth the $6 to have a wireless remote around when I do. I’ll let you know if I have any trouble with the remotes when I get them, but so far the comments on Amazon are pretty positive.