I picked up one of these for my Samsung phone at Home Depot a few days back. It is made by Enegizer and includes 2 lithium batteries. They have a selection to fit most current cell phones. They conveniently have the connectors hanging out of the back of the package so you can test the connector before purchase.

The pack claims it can be used for charging and allows you to talk while you charge. Other claims- Up to 9 hours with GSM phones and up to 3 hours with CDMA phones.

I haven't tested mine yet, but if it works as advertised, I will be getting one for each glove box, as well as my wife's emergency kit at work.

Use with lithium batteries is a real bonus- maintains voltage when exposed to temp extremes, doesn't leak (at least not in my experience) and long shelf life.

TR