I get asked this quite often. The answer is Lync 2010 and Lync Server 2010 both have 508 VPATs available here.
A couple of examples shown below:
Support for high contrast
Lync voice also allows for TTY users.
For more on the accessibility features see the Lync product team’s blog post here.
Is Lync 508 compliant?
We help you achieve compliance via VPATs which Lync Server and Lync client 2010 has. VPAT is a standardized form developed by the Information Technology Industry Council to show how a software product meets key regulations of Section 508 of the Rehabilitation Act.
Unfortunately the Lync Group Chat Client is not 508 compliant, however our browser based client for Lync Group Chat is, so for anyone out there needing it we are at fcg.im