HP's low cost, low power LX195 MediaSmart Server, based on Microsoft's Windows Home Server, is available now!
You can order it from these retailers for $399 (I'll add more as they become available). Just click on the logos below:
If you are looking for a small, low power WHS, you may want to check this one out. It comes loaded with some pretty cool add-ins that other companies don't offer. And while you're at it, be sure to order the 2GB memory upgrade with my easy to follow instructions.