I've a Nokia charger that outputs 1200ma instead of the 700ma of a BB charger.
I reckon it should be fine but would be interested to know of other peoples thoughts on this.
Posted from my CrackBerry at wapforums.crackberry.com
Provided the VOLTAGE is regulated to 5 Volts, the maximum current will not matter since the phone's internal resistance (load on the carger) will limit current inflow to the device.
The key is to make absloutely sure that the voltage output is 5 Volts. There, I've said it twice.
That said, using the original BlackBerry wall charger is still the preferred charging option.