The FindLaw Lawyer Directory (West Legal Directory) allows you to search a database of over a million lawyers and law firms to find those specializing in patents in a specific geographic area.
Another comprehensive and well-known directory of lawyers is the Martindale-Hubbell Lawyer Directory. It also allows you to search for attorneys specializing in patent law and provides profiles and peer review ratings of lawyers. Martindale-Hubbell also compile a list of the top ten law firms based on the total number of U.S. patents granted during the past two years.
PatentBuddy is a commercial site that also provides a searchable directory of attorneys. In addition to contact information, the directory also provides additional information about a patent attorney's work history with the USPTO.