from Simplehelp

Similar to How to install Ubuntu in OS X using Parallels – a complete walkthrough, this tutorial will take you every single step of the way through installing Windows Vista using Parallels for OS X.

The steps and screenshots used for this tutorial are specific to Parallels Build 1970 running on a MacBook Pro w/ OS X (10.4.8). With that said, they will be nearly identical if you have a Mac Pro, Mac Mini, MacBook or any other Intel based Apple Mac.

some additional info: As a friendly digger points out, you won’t be able to run Aero (the fancy graphics stuff in Vista) no matter how great your Mac video card is. VMWare is more likely to be the first allowing 3D in a virtual OS.