That's what everyone wants to know!
Due to Intel's NDA you won't be able to find much information on Diamondville anywhere until it's officially launched by Intel in June.
So far, this is all I can find:
Diamondville is confirmed to be the first Intel processor to support simultaneous multi-threading (SMT) since the Pentium 4. While the entire Silverthorne architecture supports SMT, only Diamondville is confirmed as SMT-enabled.
By the way, Diamondville is a Silverthorne derivative, and both fall under the Intel Atom brand. You can read the Wikipedia entry for more information:
http://en.wikipedia.org/wiki/Silverthorne_(CPU)
Silverthorne: Optimised for low-power, then low-cost.
Diamondville: Optimised for low-cost, then low-power.
This is why Diamondville has a higher TDP than Silverthorne (4W vs 0.6W-2.5W)
Some other technical information if it means anything to you - cos it doesn't mean anything to me: The 1.6Ghz Diamondville processors will be paired with Intel's 945GSE northbridge and ICH7M southbridge.
Edit: This might mean the MSI Wind is using GMA950 DX9 integrated graphics and able to support up to DDR2-800 RAM (2GB limit).