The registratin for Beta Exam 71-680: TS: Windows 7, Configuring begins April 27, and the beta exam will take place on between May 5 to May 18, 2009. If you pass the beta exam, the exam credit will be added to your transcript and you will not need to take the exam in its released form. You must register at least 24 hours prior to taking the exam, and use the promotional code during registration: WIN7J
Microsoft also has two other Windows 7 exams in development: 70-685, MCITP: Windows 7, Enterprise Desktop Support Technician, and 70-686, MCITP: Windows 7, Desktop Administrator. Guides for the Windows 7 exams have yet to be posted to the Microsoft Learning site as of this writing.
More info: TechNet Blog