Apple released iTunes 6.0.5 today, adding the ability to sync the Nike + iPod workout data with nikeplus.com. Presumably this is only for the nano.
Apparently this release quietly patches an AAC parsing flaw where iTunes could quit or potentially execute arbitrary code. The issue is addressed by improving the validation checks used when loading AAC files.
Also of note: "After purchasing music from the iTunes Music Store with iTunes 6 or later, you also need to upgrade your other computers that purchase music from the iTunes Music Store to the latest version of iTunes."