Is it possible to have an exposure longer than 30 seconds with the 30d, or would I have to go to a film body with my lens?
if you don't want to hold down the shutter button manually, get a RC1 remote (~$30). Then, you can tripod your camera, and put it on BULB mode as mentioned, and then control the shutter using the remote. This way, you won't have to hold a button for so long. Plus, it gives you an excuse to buy a new toy.
Or maybe you're like me (when I switched to my first digital SLR) and took a while to realize that you have stop your shutter speed down and down and down before you hit "bulb." Really... it's there, just not a convenient and obvious setting on the dial like the good old days.
The RC1 wont work for the 30D. It doesn't come with a wireless remote sensor. You have to buy the canon wireless remote (around 400 bucks) or an aftermarket one. You don't have many choices.