You might start your school research at Great Schools:
That site has test scores and such noted for every school. It's difficult to compare area to area, or city to city, but relatively easy to compare school to school, if you know a list of schools you want to compare. Keep in mind that many districts excel at one level in their system, while lacking in other areas (for example, they have great schools for K-8, but then suffer at high school).
As far as crime rates within the school, I would think that your best bet would be the police station. School administration probably doesn't track crime stats accurately, and would likely give a more general answer to specific questions about crime rates on campus, whereas the police should be tracking that more closely. I don't know of an online source for that information, however.