I just got this from Barbara Decker at MS, who has graciously permitted me to post it here:

The VFP exams are following the same model as the VB and VC++
exams--certifying the candidates as MCSD's--Soultion Developers. As an (MC)SD, candidates need to have an extensive skill set, including knowing how other technologies are used in conjunction with VFP. In order to pass the exams, candidates need to not only code VFP apps, but also be fully immersed in the other aspects of providing a VFP solution (i.e. developing logical design, deriving physical design, testing, deploying, maintaining, etc.).

Also, if people want practice tests, they can contact the official
Microsoft practice test provider companies, MeasureUp and Self Test Software at, respectively,

http://www.measureup.com and
http://www.selftestsoftware.com/shop/