I have had numerous questions regarding the process so I will try and clarify...
If you are taking MCSA or MCSE exams (70-461, 462,463, 464,465, 466,or 467) you will register at Prometric and use a special testing center... As soon as this setup has been complete by Prometric I will notify everyone.
If you are taking the MCM 2008 exams (either 88-970 Knowledge or 88-971 Qual Lab) or the new MCSM Knowledge Exam (88-986) then you should contact GetCert@microsoft.com (cc: AdvCert@microsoft.com).
The Advanced Certification team will manage the scheduling of these exams, not Prometric.
There are a limited number of discount vouchers still available, but you must have the Advanced Certification team schedule you in order to receive these discounts.
As alway if there are any questions please reach out to me at firstname.lastname@example.org