State bar association websites can be a good resources when researching professional responsibilities issues in a particular jurisdiction, but you may end up doing research on Lexis or Westlaw, especially if you are looking for a jurisdiction-specific treatise, bar journal article, or if you need to search for ethics opinions, but don't already have a citation to a specific opinion.
Cases: Search state case law databases for ethics cases that have been adjudicated in state courts.
Statutes: Search relevant statutes and court rules for the legal issues you are researching in your jurisdiction. Some annotated state statutes will include ethics opinions in the case annotations.
Bar Journals: State, city and county bar journals contain articles that are written by practicing attorneys in that state. These bar journals can be a particularly rich source of articles on the legal ethics rules which are specific to that jurisdiction. Note that not all jurisdictions will have a bar journal. You can find federal, state, city, and county bar journals on Lexis and Westlaw from the 1990s - current.
State Ethics Opinions: Remember that State Ethics Opinions are advisory, but not binding. Lexis and Westlaw do not carry ethics opinions for all jurisdictions - check for coverage: