Well, they’re not just giving it away to everybody. Microsoft is giving away copies of the Server 2008 R2 standard edition as part of their DreamSpark program. DreamSpark is Microsoft’s initiative to give away some of their most powerful tools to students, allowing them to learn how to use the products for free (instead of just pirating a copy off the web).
All you’ll need to do is provide some information that proves your status as a student, and you’ll be able to download an IMG file and install a full working version of Server 2008. Sounds like a pretty good deal. There’s a bunch of other software in the DreamSpark program, so if you’re a student it’s definitely worth your time to check it out. And don’t forget, you can still get a discount on a copy of Windows 7 when it comes out.