Apple responded quickly to reports that its initial release of iTunes 8 caused STOP errors (Blue Screen of Death) on some Windows machines. The issue is documented in  support article TS2280, “iTunes 8: If Windows Vista displays a blue screen error message when connecting iPhone or iPod,” which tersely describes the symptoms:

After installing iTunes 8 for Windows, some users may see a blue screen error message when connecting iPhone or iPod to a Windows Vista computer. In some cases, the computer may immediately restart when connecting iPhone or iPod to the computer.

The recommended solution is to first uninstall Apple Mobile Device Support and iTunes, and then download and install the most recent version of iTunes. (Delete any previously downloaded versions.)

ZDNet