If you're at all handy with a soldering iron, this is a fun project to do what you need : http://www.ladyada.net/make/mintyboost/
Tekkeon's TekCharge MP1550 is a beefier version of this; it will work with two or four AA batteries, and provides USB. If you put rechargeables in, it can also charge them via a secondary charging port. This has become my solution of choice for backup power for power-hungry cell phones that drain their batteries every other day. The flexibility of being able to stop at any store and buy a pack of AA batteries in a crisis is great. For me, it's passed the pocket-indestructability test of having survived more than three months unprotected in my pocket, which typically does plastic thingies in. ... JG -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "We call it the 'one bite at the apple' rule. Give me one chance [and] then I won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN) With 24 million small businesses in the US alone, that's way too many apples.