iTunes 8.1 alert

[pam123]

Apple may have a major bug in the latest iTunes install (8.1), the new version of Genius will freeze iTunes when it tries to update.

Initially this looked like a Vista problem but now there are reports of the same problem in XP.
I'm not sure about Macs but one poster has, so far, reported the same problem with his Mac as well as his XP machine.
There's actually been an Apple Tech on the discussion board giving instructions for collecting and sending crash reports to Apple and this is rare.

If you're already stuck then the solution is to re-name the Genius file in the library and force iTunes to create another.
It won't work as advertised but it won't crash iTunes either.