Heard on a web cast today that the new generation of Microsoft certifications will have a limited life.
Technology Specialist (MCTS) will expire when a new version of the technology is released. The exam will remain on the transcript but the certification will no longer be valid.
IT Pro (MCITP) and Professional Developer (MCPD) certs will have a 3 year life though there will be a "recertification" exam of some sort.
While this is a big chnage in the Microosft world it does bring them into line with the like of Cisco who have had a 3 year life on their certs for a while.