Apple recent posted Digital Camera Raw Compatibility Update that includes the new Canon Digital Rebel (and others listed to the left). This is news because Apple has responded much faster this time around than with the Canon 40D and Nikon D3 and D300.
If you're a Leopard user, you can also get the new Raw profiles via the Mac OS X 10.5.3 update. You can read about the Leopard update on this Knowledgebase document If you're not ready for all of that, but want the profiles, then just go with the Digital Camera Raw Compatibility Update. Both are available via the Software Update menu on your Mac.