I just got my advance copy a few minutes ago via UPS. I already have the Kindle version for a few days and I have been reading that. I’ve seen parts of the book as the authors were writing it but now I can read it as a whole. I’ll be doing a book review soon – probably next week sometime.
You can purchase the book here – http://www.amazon.com/Professional-Unified-Communications-Development-Microsoft/dp/0470939036/ref=sr_1_2?ie=UTF8&qid=1305817868&sr=8-2#_