Actually, it's a little complicated than that, and it's been all over the web
"Microsoft is running an unadvertised sale on Windows Vista. For the price of an upgrade edition requiring an existing copy of Windows, anyone can have a stand-alone version of Vista that will run on any PC. Indeed, the upgrade editions are full versions, simply waiting to be told to install themselves regardless of what OS is currently on the system, if any. The trick is all in how you interact with the setup program..."
And w/ this method you can also dual boot w/ your current OS, too; however, do this at your own risk because based on the latest news from M$, it's illegal to do that.
Have fun,
[www.jlbn.com] (testing WAMPS on Vista)[test.jlbn.com] (testing codes on Vista)Win Vista Business
Apache
2.2.4MySQL
5.2.3 F-APHP
5.2.1SSL
0.9.8DphpMyAdmin
2.10.0.2