I was just talking to someone about how neat it would be if I could install the latest Vista built in Parallels, he agreed and hoped that his Mac Pro would soon be able to run Parallels in 64 bit mode soon (he has it hacked to run in 32 bit mode at the moment). Imagine my glee (yeah, I get gleeful over software updates) when I saw this post on Parallels blog.
Parallels Desktop for the Mac can now run on Mac Pros with up to 3.5 gigs of RAM (things get funky with more RAM), it supports running the developer previews of both Leopard and Vista, and USB support has been improved. Get the full details here.
This update is free.