An update to iTunes is available, which is basically a security update to address an issue where a maliciously crafted website could lead to the application quitting or arbitrary code being executed. According to Apple's knowlegebase article on the security content of the update, the bug at hand occurs when a buffer overflow in the handling of iTunes URLs (itpc) is exploited.
Other than this bug fix, the iTunes update includes the following bug fixes over the prior version:
Disables older versions of some incompatible third-party plug-ins
Addresses minor issues with dragging and dropping items
Addresses a performance issue when first syncing to some devices with iTunes 9.2
Addresses an issue upgrading to iOS 4 on an iPhone or iPod touch with encrypted back-ups
Addresses other issues that improve stability and performance
The update should be available through Apple's Software Update program for both Windows and OS X, but can also be downloaded from the following locations:
As always, be sure to fully back up your system and the mobile devices you use with iTunes before updating. Keep in mind that updates can affect other system features as well (just like the recent Safari update affecting Mail's attachments) so be sure to check the aspects of your system you commonly use after updating. So far this update has installed just fine with no problems on my MacBook Pro (2.66GHz, 4GB RAM, 10.6.4).