I am at TechEd this week, where we are announcing our new presence-powered real-time expert finder, Clarity Connect.
I wanted to point out two books that are great resources if you are doing any kind of development with the Microsoft Unified Communications platform.
The first is the Office Communications Server 2007 R2 Resource Kit. This book focuses on the structure and configuration of Office Communications Server, and is a good read if you want to get a comprehensive idea of how OCS works, which can be very helpful for development.
The second is Programming for Unified Communications, which is due to be released very soon. This book actually delves into development with the UC APIs, and should be an indispensible resource once it comes out.
The OCS Resource Kit book is also on Twitter — you can get bits and pieces of OCS info at http://twitter.com/DrRez.