The news is all over town (CNET, Yahoo) that Apple is advising iPod owners not to upgrade to Vista until they release an update to iTunes:

iTunes 7.0.2 may work with Windows Vista on many typical PCs. Apple recommends, however, that customers wait to upgrade Windows until after the next release of iTunes which will be available in the next few weeks.

(Source: http://docs.info.apple.com/article.html?artnum=305042)

The only good reason Apple has for not having an iTunes update available already is so it can leverage “potential incompatibilities” to discourage consumers from moving to Vista.  Apple is blatantly using its dominance in the portable media market to attack its new OS X rival.

With OS X 10.5 (codenamed “Leopard”) scheduled for release by spring 2007, it is in Apple’s best interest to dissuade consumers from adopting Vista for as long as possible in the hope that some of them will consider a Mac instead of a Windows upgrade.  But I think this tactic is backfiring as the negative backlash grows in the blogosphere.