Has anyone had any experience with the Belkin Battery Pack for iPod? They sell'em over at the apple store (http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/70602/wo/Fq3Xkb7pXGyJ2jOvAmmeB7tPuB5/9.7.0.5.1). Sounds like a nifty toy to have, can come in handy in long trips!