www.worldcat.org. On their Find a Library page, you can enter a zip code or city name and see a list of libraries and the distance to them. Note that ALL types of libraries are shown, even school libraries, so you may need to refine by type on the left side of the screen:
Another option for library services for health professionals is an AHEC, Area Health Education Center. The AHEC program was started in the 1970s to support health professionals working with underserved populations by providing continuing education, information dissemination, and other professional support. There are 54 AHEC programs with more than 200 centers in the U.S. Find one near you using the National AHEC Organization's directory.
Another link you might find helpful is this list of Medical/Health Sciences Libraries on the Web, arranged by state, from Hardin Library for the Health Sciences at the University of Iowa.
So, what's a great library in your community?