The Microsoft Certifications blog has announced availability of two beta exams:
Space permitting, you can take these beta exams for no charge.
Beta exams are longer, but count for the same credit as the exam in released form and you’ll be helping Microsoft improve the exams for final release.
Going to PDC10? You can take these exams at the PDC testing lab in building 40 from 10/27 through 10/29.
Logistics are described here.