Microsoft's approach to VoIP is the one we all were looking in the old Asterisk <-> Live Communication Server <-> Exchange Server days. Where we all wanted handling all things from a centralized AD much more simply rather than a non-solid platform for integration.
The Software Development Kit for the Microsoft Unified Communications Managed API version 1.0 (UCMA v1.0) includes documentation of the API, sample applications that use the API, and a redistributable package. UCMA v1.0 is an endpoint API that provides the flexibility and scalability required by advanced developers to build and integrate server applications (e.g. alert broadcasting, persistent chat, instant messaging response bots, etc.) into an existing Microsoft Office Communications Server 2007 infrastructure.