iCleaner is a junk file remover for iOS (I guess you can say it's kinda like how CCleaner clears out junk on computers). I'm guessing jonthedit suggested it in case a piece of malware decided to make its home in the caches or something.
It's very unlikely that your iPod is infected (the only malware I know of is a worm that requires the target to be jailbroken and have SSH access), but that's not to say it isn't possible, as Apple stopped pushing iPod touch 2G updates.