In a recent post I commented on the URL that discusses OCS Compatible Headsets, well for those with the Microsoft LifeCam you will have noticed that whenever you click the top button it fires up Windows Live Messenger, which can be annoying. The following BETA link explains how to prevent this from happening in your Org.
Microsoft headsets and webcams are optimized for Windows Live Messenger through the Call Button. Until now, there has not been a simple means to configure the Call Button to start Office Communicator. The goal of the Call Button Integration Support kit