These materials, apparently course material from the New York County Lawyers’ Association, include a very general treaties on legal malpractice, as well as specific information for investment and accounting professionals. While the materials are focused on New York law, they do provide a very good overview of legal malpractice in general.
The website Justia.com provides a short overview of legal malpractice without any citations for case references. Of considerably more usefulness is American Bar Association’s 50 state survey legal malpractice law. These materials, however, are available only to ABA members.