The latest MoneySavingExpert.com newsletter links to glovebox emergency mobile chargers for ~£10. Play.com have a similar item for half that!
* Up to 1.5 hours talktime from 1x AA Battery
* Re-usable power - again and again
* Connect to phone and tsalk whilst charging
* Multiple connectors allow charging of wide variety of phones
* Handy built in L.E.D Torch
*Comes with mini-USB B cable (Motorola etc.), 2nd generation Sony Ericsson (k750,w800 etc.) Nokia size 1 and 2 (old cable adapter. 2310, 1110 etc. And new narrow cable adapter. N Series, 6300 etc.), and also the samsung "E900" adapter (for most of the samsung models. E900, E250, J600, C170, M300. NOT G600, J700, F210 or any new models!)
Don't every be stranded again with a dead phone - no charger or the wrong mains plug - on holiday or in the car, just put a standard AA battery into this small charger and simply plug in and go.
Emergency Mobile phone charger, simply plug in and talk - anytime, anywhere, Up to 1.5 hours talktime from 1 X AA battery, also includes built in LED torch.
Also available in white here - http://www.play.com/Mobiles/Mobile/4-/5376687/Emergency-Mobile-Charger/Product.html