The Sixth Circuit Court of Appeals in a decision against federal investigators, ruled that the email users have a reasonable expectation of privacy. In Warshak v. U.S.A. the federal government had argued that email stored with service providers could be seized without warrants and without notice to the account holder. The case was heard by a three judge panel, so it could be appealed to the full court of appeals. There is a local connection, as the Boston Globe article mentions that the attorney for the defendant is from Boston, Martin G. Weinberg.
If this interests you, see our pages on Internet and Online Privacy, Privacy, and Employee Privacy.