At the James Publishing weblog, Dorothy Clay Sims has a book excerpt titled "Checklist for Researching Defense Doctors," which includes a number of tips that will work for researching doctors hired by either side in a case.
Sims lists these sites, among others--
- Florida Med-Mal Claims Information
- Florida Office of Insurance Regulation
- AMA Links to State Medical Boards
- National Register of Health Service Providers in Psychology
- Google Scholar
To get the specifics as to the best way to use these sites (as well as some other sites I omitted from the list), you should read the full post.
Sims' post also also includes detailed instructions for using eight different databases within Lexis for researching medical experts. Sims' book is titled Exposing Deceptive Doctors.