I just got one and I'm a little annoyed it doesn't have a wall adapter included. I have a USB/miniUSB cable, but I'm not sure if it charges the unit. When I plug it into my computer or use my iPhone USB wall charger adapter it turns on, but I can't do anything else with it, so I don't know if it's charging.

Does anyone use a USB cord with their unit, and if so, does it charge it or just power it?