The Nitro battery is model number BL-49kh. Not many cheap OEM options out there right now, but an "official" spare can be purchased from AT&T store:
http://www.wireless.att.com/cell-ph...ssoryBucket&q_sku=sku5520227#fbid=aQi6sm_4Fs8
Here's a few charger options...
Portable Chargers
Duracell Portable USB Charger
Car Chargers
Motorola Vehicle Rapid Charger
Kensington HIGH Current car charger
Hybrid Chargers
Boxwave AC/Car/Airplane USB Charger
http://www.wireless.att.com/cell-ph...ssoryBucket&q_sku=sku5520227#fbid=aQi6sm_4Fs8
Here's a few charger options...
Portable Chargers
Duracell Portable USB Charger
Car Chargers
Motorola Vehicle Rapid Charger
Kensington HIGH Current car charger
Hybrid Chargers
Boxwave AC/Car/Airplane USB Charger