Live Communications Server 2005 provides a manageable and scalable enterprise-grade real-time communication solution for your organization. Extending from the same Session Initiation Protocol (SIP) and SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE)-based industry standard platform as Live Communications Server 2003, Live Communications Server 2005 will enable better business decisions even faster than previous versions by allowing you to share presence, instant messaging (IM),and real-time communication capabilities with partners, customers, and suppliers.

URL: http://www.microsoft.com/office/livecomm