Needing to buy a wireless trigger can be avoided, see below...
Okay, Kory, remember when we were having a quick chat about setting up your external flash to fire without using the wireless trigger? I've tried it with the new camera and it works the same way as with the 450D, so it should work for your camera too (and most likely yours, too, Owen). The only issue will be if you don't want to use your on-camera flash. Otherwise, set your flashes up in slave mode, and once you've set your on-camera flash to fire, it should signal the external flash(es) to go off. I'm pretty sure there is also a way to do it without the built-in (or a hot shoe-mounted) flash, but haven't read up and experimented with it yet...
Oh yeah, thinking about it, the external flash(es) should overpower the built-in flash anyway, so hopefully you'll still be able to get a nice even spread of light.