If you were one of the many people who were caught up in Prometric's 71-663 (BETA: Designing and Deploying Messaging Solutions with Microsoft Exchange Server 2010) snafu, you can now take the public released version and upgrade (or obtain) your MCITP: Messaging cert -- for free with your voucher code.
For those who aren't aware of what happened, Microsoft Learning typically invites people to take Beta exams via email invitation based on your SME profile on MS Connect. They send many emails out but typically limit the number of people who can actually register and take the beta exam to 300. Apparently Prometric didn't cap the registration at 300 so many people registered for the beta and were ready to take the exam. A few days/weeks later most people received an email that their exam was canceled with an explanation of the problem. The up side is that Microsoft sent these folks out a voucher so that you could take the exam for free when it went public.
Study hard and good luck!