Very cool! UCCA replaces the RTC 1.3 SDK and adds Vista support. You can download the Microsoft Unified Communications Client API SDK here. 
Oh and in case you forgot, to the right is Microsoft's Communicator client, a SIP-based communications application that integrates VoIP, IM/presence, video, collaboration, and more. On a related note, Bill Gates and Jeff Raikes will kick off the worldwide Unified Communications Launch 2007 in San Francisco on October 16 (this Tuesday). This is a huge launch for Microsoft and officially kicks off the launch of Office Communications Server 2007 - the core of Microsoft's Unified Communications strategy.Microsoft's Unified Communications portfolio covers a lot of components, so here is a chart listing the various programmatic interfaces to the various components, which developers might find useful:
| Unified Communications API | Description |
|---|---|
|
Unified Communications Managed API version 1.0 |
A .NET Framework-based API for creating and deploying server-like or middle-tiered real-time communications applications. It is especially useful for applications with high scalability requirements. |
|
Unified Communications Client API |
A COM-based API for creating and deploying client side real-time collaboration applications. Microsoft Office Communicator is a desktop client built on the Unified Communications Client API. |
|
Office Communicator API |
A COM Automation API to enable programmatic access to Office Communicator. It is useful for applications that extend Office Communicator to offer customized functionalities. |
|
Communicator Web Access API |
An AJAX Service-based API for creating browser-based client applications. It is especially useful for applications that must be operating system independent. |
|
Office Communications Server API |
For managing servers and creating server applications. |
|
Live Meeting Service API |
An XML-formatted API for programmatically accessing Microsoft Office Live Meeting Web Service. |
