http://www.macnn.com/articles/09/10/22/most.newer.systems.to.work.in.64.bit.mode/
Apple pledges full Windows 7 support in Boot Camp
updated 02:55 pm EDT, Thu October 22, 2009
Most newer systems to work in 64-bit mode
Apple has pledged full support for Windows 7 through Boot Camp in Snow Leopard before the end of the year. Many Macs already can run Windows 7, although users have reported varying levels of compatibility. Not all systems are able to run in 64-bit mode, while certain hardware drivers currently create problems. The Boot Camp software update will enable Macs to load Microsoft's Home Premium, Professional and Ultimate variants.
While most newer Intel-based Macs are expected to get full Windows 7 support, Apple warns against running the OS on a number of older systems. Macs that will lack support include 2006-model 17- and 20-inch iMacs, 15- and 17-inch MacBook Pros, and Mac Pros with Intel Xeon 2.66GHz or 3GHz CPUs.
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Release candidate
We have been running the release candidate for two months on my wife's Mac Mini with almost full support....no audio drivers yet.