EOS utility comes on the disc with your camera. That's what the guy above me is talking about. I use it because I haven't bothered to pick up an actual intervalometer yet, and it works super easy as long as you don't mind having your computer wherever you're shooting. You can adjust any other settings on the camera through that software too.
The intervalometer part of the program is the stopwatch button. That's where you pick your interval and how many shots you want.