"Windows is a legacy OS," [Apple Senior Software Architect Cameron Esfahani] said to laughter and applause from the crowd. "We don't have legacy support."
According to this article, only 64-bit versions of Windows Vista will boot via the Extensible Firmware Interface (EFI) that Apple uses on its Intel Macs. Apple is only using 32-bit chips thus far, so versions of the new Microsoft OS that will be compatible with the processor architecture will likely still be using the Basic Input/Output System (BIOS) to boot and load core services.
This means that there will be no version of Windows Vista that will be able to run easily and smoothly on the Intel machines from Apple. At least Apple hasn't made any promises... the desire to run Windows on a Mac has been created entirely in the minds and hopes of users, and has not been specifically egged on by Apple or its officers in any way.
I think it was Phil Schiller who said that Apple wouldn't stop users from attempting to run Windows on MacIntel machines, but that doesn't even admit that there is a possibility that it will ever even work with the fluidity that seems to have been expected by Mac users worldwide.
I agree with Cameron Esfahani... if Windows Vista does not support EFI in every one of its numerous versions, it is a legacy operating system that has no business parading as the "next new thing" in the modern computing world.
(No Vista on Mac's horizon | CNET News.com)