Windows users seeking refuge from malware don't have many places to go, including Apple's iOS App Store, which was recently discovered to be harboring files containing a Windows virus. A user on Apple's support forum first reported the discovery after ClamXav flagged his "InstaQuotes-Quotes Cards for Instagram" download as being infected.
The app developer was able to sneak a worm into the program (or did so unknowingly, perhaps because his own system was already infected), which could infect Windows users who manage their iTunes account on a Windows PC, but is not a threat to either the Mac OS X or iOS platform. Not to overstate the threat, even Windows users would have to manually extract the infected bits of code from the application package for it wreak havoc, and even then, most virus scanners, including Microsoft's free Security Essentials program, would pick it up.
Still, it's pretty interesting to see Windows malware reside in an iOS file, and it should serve as a warning to Windows users never to let their guard down, even when grabbing apps from a different platform. In this specific case, Apple has removed the offending program.