Mac OS X 10.4.11
, released yesterday through the Software Update mechanism of Macs running an earlier version of OS X 10.4, adds the ability to view and process Canon EOS 40D RAW CR2s in applications that utilize the operating system's RAW support, including Apple's own Aperture and iPhoto.
Among the changes in Mac OS X 10.5 Leopard, released on October 26, 2007 as a paid-for upgrade to the Mac OS, was the addition of support for EOS 40D RAW CR2s as well.
RAW files from the Leica V-Lux 1, Olympus EVOLT E-410, Olympus EVOLT E-510 and Panasonic Lumix DMC-FZ50 are also now compatible, in both 10.4.11 and 10.5.
A complete list of the RAW files supported in OS X 10.5 is here