Considering there is no virus scanner application for iPod at this time, the only way to get a virus off an iPod is to restore the device back to factory specifications. This process removes the contents of the device, Operating system and all and waits for you to connect it to iTunes again in order to re-load the operating system. iPod touches and iPhones can be purged by an option on the iPod screen within iTunes for PC/Mac. It will do this by default for any device that has had it's hard drive wiped or formatted. Also you can try scanning it with your antivirus software - works only when you've ticked "enable disk use" option in iTunes.