Gizmodo
Sometimes you can't annoy the other patrons at the coffee shop with a puny iPod speaker. The PodXtreme Sound Box is a small add-on speaker for the iPod that is capable of generating a "powerful sound" and "powerfull bass boost" even though the device is half the size of your actual iPod. It runs on lithium-ion batteries and is juiced with a USB connection. And it really isn't limited to the iPod, given that it plugs in via the standard audio jack, but they have to milk the iPod market somehow. $30.
Product Page [Via Red Ferret]
