A bug in Vista has required Apple to advise users to only eject an iPod from within iTunes or risk data corruption. Now Microsoft has issued a patch that fixes the problem.
The patch for Vista is listed under KB933824 at Microsoft.com
The patch says, "Install this update to resolve an issue where an Apple iPod may be corrupted by using the Safely Remove Hardware feature on a system running Windows Vista. After you install this item, you may have to restart your computer."
Apple patched iTunes earlier to version 7.1.1 to fix minor issues with Vista, but this one had to be issued by Microsoft.