It has been over two weeks since Apple officially introduced us to their new iOS-based wireless printing technology caleld AirPrint. Back then, the new feature was reported to be supported on iPod Touch 2G and later and iPhone 3GS and later. Bizarrely though, the press release and the AirPrint page on Apple have been silently modified since then to note that the feature is actually supported on iPod Touch 3G and later (and not 2G as was initially proclaimed).
It is not clear whether Apple has merely corrected a typo that existed earlier in their press releases or if this is a technical/business decision to not allow this new technology on the older iPod Touch model.
Nevertheless, this is not an entirely surprising decision. The second generation model of iPod Touch is pretty close in technology to the iPhone 3G unit and considering that AirPrint is not supported on iPhone 3G, it is pretty reasonable to expect Apple to pull the strings this way.