Hi Craig,
Apple recently added support in ImageIO (part of the OS) for the 1Ds Mk III (and other models like the Nikon D3 and D300), but only on 10.5.2 (Leopard). They probably could have posted a "Digital Camera Raw Support Update" as they did prior to 10.4.9 (to avoid a complete OS update) so that third party applications running on 10.4.11 could support the newer camera models, but to be quite frank Apple apparently only cares about their own photo applications (note that Aperture 2.0 and iPhoto 7.1.2 can handle these new cameras on 10.4.11). You will have to pay Apple to upgrade to Leopard and wait for PM 4.5.3.1 (free update) to get access to RAW conversions for your camera (or you could use iPhoto or buy Aperture 2.0 which is what Apple would like you to do).
Even though we pay Apple $500 a year for developer fees, they keep us in the dark about details of updates and also don't give us full access to the raw processing features that come built-in to the OS (that you paid for). They limit full RAW access (and other goodies like the "Pro" interface elements) to their own applications. If you think this is unfair anti-competitive monopolistic behavior then you can try and take this up with Joe Schorr, Apple's Senior Product Line Manager for Photo Applications. I don't have his email address handy but employees of large corporations often have an email address with their first initial and last name.
Sorry...
--dennis
