Hi,
there is no requirement to have certain years of experience. But you should have the knowledge to pass the exam. And from my experience with exams, experience is really really helpfull. So whenever I prepare for an exam, I do as moch exercise as possible
in all topics that are relevant for the exam. (So as I am concentrating on the isual Studio exams, I am doing a lot of small programs ad playing around a lot with classes that are related to a topic.)
You can find details on your named exams here:
http://www.microsoft.com/learning/en/us/exam.aspx?ID=70-441&locale=en-us
http://www.microsoft.com/learning/en/us/exam.aspx?ID=70-442&locale=en-us
"This exam will be retired on June 30th, 2011."
Please see
http://www.microsoft.com/learning/en/us/certification/exam-dev-release.aspx for a FAQ about this retirement topic (Last tab!).
So maybe you want to have a closer look at some other exams instead?
http://www.microsoft.com/learning/en/us/certification/cert-sql-server.aspx is a good entry point to check currenty available SQL Server certifications.
With kind regards,
Konrad