It sounds pretty cool - just check out the details:
Dial-in audioconferencing - Office Communications Server 2007 R2 enables businesses to eliminate costly audioconferencing services with an on-premise audioconferencing bridge that is managed by IT as part of the overall communications infrastructure.
Desktop sharing - This feature enables users to seamlessly share their desktop, initiate audio communications and collaborate with others outside the organization on PC, Macintosh or Linux platforms through a Web-based interface.
Persistent group chat - This enables geographically dispersed teams to collaborate with each other by participating in topic-based discussions that persist over time. This application provides users with a list of all available chat rooms and topics, periodically archives discussions in an XML file format that meets compliance regulations, provides tools to search the entire history of discussion on a given topic, and offers filters and alerts to notify someone of new posts or topics on a particular topic.
Attendant console and delegation - This allows receptionists, team secretaries and others to manage calls and conferences on behalf of other users, set up workflows to route calls, and manage higher volumes of incoming communications through a software-based interface.
Session Initiation Protocol trunking - This feature enables businesses to reduce costs by setting up a direct VoIP connection between an Internet telephony service provider and Office Communicator 2007 without requiring on-premise gateways.
Response group - A workflow design application manages incoming calls based on user-configured rules (e.g., round-robin, longest idle, simultaneous), providing a simple-to-use basic engine for call treatment, routing and queuing.
Mobility and single-number reach - This extends Microsoft Office Communicator Mobile functionality to Nokia S40, Motorola RAZR, Blackberry and Windows Mobile platforms, allowing users to communicate using presence, IM and voice as an extension of their PBX from a unified client.*
APIs and Visual Studio integration - This improves the efficiency of everyday business processes by enabling businesses to build communications-enabled applications and embed communications into business applications.