This Minty Boost DIY USB recharger uses a pair of AA batteries to power a USB socket. It’s fairly simple to make, fits inside an Altoids tin and can recharge a whole bunch of devices. You can buy the complete kit, just the PCB and if Altoids aren’t sold in your country, they’re happy to sell you the tin as well. It won’t fully recharge the newer iPods, the batteries are too big, but they will half fill them. Click through to the website for the compatibility list. US$19.50 for kit, excluding the tin and batteries.
This project details a small & simple, but very powerful USB charger for your mp3 player, camera, cell phone, and just about any other gadget you can plug into a USB port to charge! [Thanks Gilbert]