Not only that, but Google will be able to help you. This is an open design, the information is there for the asking.
Premier Farnell recommend the following power supplies:
- Model A: 5V dc, 500-700mA
- Model B: 5V dc, 700-1200mA
From just one of the hits Google gave me.
Note that power requirements vary depending what the device is doing, so if you want to be really tight, you'll have to measure it.