CenterWatch
10 Winthrop Square, Fifth Floor, Boston, MA 02110
(617) 948-5100
Excellent site for finding clinical trials of interest in your area, as well as learning about clinical trials and participating in them
ClinicalTrials.gov
ClinicalTrials.gov is a service of the U.S. National Institutes of Health, and is a registry and results database of publicly and privately supported clinical studies of human participants conducted around the world.