I was one of the many that were upset when Microsoft dropped Pearson Vue in favor of Prometric for their IT certification exams. Now, Microsoft is dropping the contract with Prometric, and is renewing with Pearson Vue. This is excellent news for many, as the nearest Prometric test center for me was 4 hours away (similar to many others). Pearson Vue has more centers available. Now, I can say that I am going to finish my CCNA: Security and then move on to many more Microsoft exams (Windows 8, Windows Server 2012, etc..). A FAQ for details is available here (PDF).
The partnership officially ends on December 31, 2014, however on September 4, 2014,Pearson VUE will renew its authorization as an exam delivery provider. Microsoft certification exams will continue to be available through both exam delivery providers through December 31, 2014.