The AMD X2 doesn't really have an FSB, it uses Hyper-Transport Technology. The HTT on the X2 is 2000MT/s, or 1000Mhz I believe.
The A64 (and X2) line have a 5x HTT multiplier, to find out the speed, multiply it by the bus. So 200 x 5 = 1000Mhz HTT.
Hope that helped.