Even though the first DDR3 modules are barely available yet, memory makers are already doing their best to clock them as high as possible.
1066MHz and 1333MHz modules are already available on the market but the current chips are so overclockable that by next month we can already expect the first DDR3 modules that will be clocked at 2000MHz or more.
You don’t gain much performance, but hey it’s a cool number. Jedec certifies DDR3 at 1066,1333 and 1600 but no more than that, but you can always overclock if you want to go faster.
With a good motherboard, P35 chipset and only a few extra of volts, you will be able to get over DDR3 2000 speeds and that is what many birds wants to show at Computex.