Messenger for Mac 7 is an integrated communications client that enables you to communicate with contacts within and outside your organization. Messenger for Mac 7 is a Universal application that is built to run on both PowerPC-based and Intel-based Macs and makes it easy to take advantage of the full power of real-time communications.

http://www.microsoft.com/mac/downloads.mspx?pid=Mactopia_Office2008&fid=8FE8C32A-6D7A-482B-97C6-42562F089EE4#viewer