A recent AVG signature file update is incorrectly identifying iTunes/iPod files as viruses, as reported by forum users on the Apple website.
The AVG Virus scanner identifies all iTunes/iPod related files as the 'Small.BOG' trojan - a trojan which does not seem to exist, as revealed by a quick Google search. The update, which is unidentified, but confirmed to be a false positive, is removing all files, and deleting them. Once these files have been "cleaned", iTunes will not run, and is not fixable by a reinstall.
A fix has been pushed by AVG in the latest signature update - but users may need to reinstall iTunes. A fix can be found here on the Apple Forums.
AVG is a free/paid antivirus solution offered by AVG Technologies, and is renowned for its' high virus detection rate, and is currently rated 4th in Neowin's "Definitive Best Antivirus 2009" poll on our forums.
iTunes has also been in the news lately due to Apple deciding to remove the Palm Pre's ability to sync like an iPod, by pushing an update which prevented iTunes from synchronizing with devices that falsely identify themselves as an iPod. Palm has updated WebOS to utilize a new way of spoofing the Pre's identity.