My brother uses the black cloth that came with his Mac, since that is a bigger size than the one that comes with the Touch/iPhones.
pre-moistened lens cleaner wipes.
http://www.amazon.com/Zeiss-Pre-Moi...=sr_1_10?ie=UTF8&s=hpc&qid=1278644530&sr=8-10
Windex.... lol just kidding.