ANY charger that puts out 1000mA will work with it. Motorola makes "travel" wall chargers that sometimes go on sale for a buck, and have the plug folding into them so it takes less space in a bag. As long as it has a micro-USB plug or takes your USB cable, it will work, does not have to be specific for the phone.
The whole idea of microUSB chargers is part of a larger EU plan to allow for standard chargers with microUSB tips, so you can replace your cell phone but "never" have to replace the wall wart for it.
Just check the power output, most of the Motorola chargers put out 1000mA now because some phones with big batteries (like the Atrix) can use that power to charger quickly. Lower power rating, longer charge times.