John,

Currently the rules for certification are fairly simple. A cert is good until one year from the retirement of the exam. So far exams seem to retire about one year or so from the release of a new product. Given that and the expectation that .NET is about a year off from now, I would guess that current certs are good for approx three years from now, one year to get the new product, one year to get the new exam out and then a year from that for the current cert to expire. That for the MCP level.

As for MCSD, well again the expiration is one year from the retirement of the current cert. That would again put us at one year to the release of .NET, another year for the new exams to be prepared, adn then one more year for the expiration of current certs. I am guessing that anyone currently MCSD certed with VFP as their core language would have a cert that is good for three more years. Plenty of time to prepare and test for replacement core exams.