http://blogs.technet.com/danieg/archive/2009/07/02/ocs-federation-with-windows-live-now-free.aspxFederation is an important goal for the Office Communications Server team and we are excited to announce several changes to public IM federation between Office Communications Server and public IM networks, effective July 1, 2009: · The Live Communicationsen-USCommunityServer 2.1 SP1 (Build: 61025.2)