From July 1st PIC with windows Live will be at no extra cost.
Licensing requirements for Public IM Connectivity depends on the service providers you want to connect with and your Communications Server client access licenses.
Windows Live: Customers with Office Communications Server 2007 R2 Standard Client Access License or Office Communications Server 2007/ Live Communications Server 2005 SP1 Standard CAL license with active Software Assurance (SA) qualify for federation with Windows Live Messenger without additional licensing requirements. Customers who do not meet the qualifying requirement should buy the Office Communications Server Public IM Connectivity license for federation with Windows Live Messenger.
AOL/Yahoo!: Federation with AOL and Yahoo! requires the Office Communications Server Public IM Connectivity (PIC) per user subscription license. The PIC License provides connectivity to both IM service providers. There are no license options for connectivity to only one provider, but administrators can choose which service provider they provision.
The Office Communications Server PIC license is sold separately on a per-user, per-month basis as a Microsoft service. PIC service licenses are available for Microsoft Volume License customers only.