Microsoft has officially launched the Windows 8 Developer Preview at its BUILD conference this morning, with the download actually becoming available later this week in the new Windows Dev Center, but if you're at BUILD, you'll get your copy there. In addition, they've also announced the Windows Store - yep, it's pretty much like the Mac App Store, but, for Windows. The store will include Metro-style apps (think Windows Phone 7 UI) as well as the more traditional Windows apps that you're used to. We'll be going hands-on with the Windows 8 Developer Preview in just a bit, and will report back with our thoughts!