Woohoo! Get it now before the Download Servers are overwhelmed. I see it is up on Connect (if you had previously been accepted into the Beta), and you can download it as an IT Pro or Developer from the Beta 3 site.
What's the address you ask? You'll have to watch this video to find out 😉
I will post some technical information over the next few days, but in the meantime, feel free to browse the Windows Server Code Name "Longhorn" Technical Library.