Greg Shields is an MVP and a partner at Concentrated Technology; you can find ITPro tips and tricks by Greg at ConcentratedTech.com. You can also find a description of Microsoft’s certification program by Greg over at TechNet Magazine in his August 2009 “Geek of all Trades” article, “Microsoft's New Certifications: What They Are, Why They Matter.” The article’s summary is

With the Microsoft Certified Systems Engineer credential being retired for all iterations but Windows Server 2003, a new certification program has been created. Greg Shields explains how this new certification path helps to better identify where your skills lie.

Greg quotes MSL’s Senior Certification Manager Jim Clark and offers a simple reason for pursuing certification:

In December 2008, technology research giant IDC commissioned a study looking at the organizational performance of more than 2,000 teams of IT professionals. The study concluded, quite impressively, that: "Unequivocally, certification, as a measure of skill, showed a positive correlation to performance improvement." Researchers also stated that 75 percent of IT managers studied believe that certification is important to team performance and 66 percent believe that certification improves the level of service and support offered to IT customers.

While these results don't directly state that certification will help you get that promotion or pay raise, they do indicate that those who certify provide greater benefit to their businesses. In today's economy, that can be a significant competitive advantage.