The estate of Martin Luther King Jr. sued CBS Inc., alleging that the New York-based broadcaster is illegally selling videotapes that contain key portions of the civil rights leader's famous 1963 "I Have a Dream" speech. The copyright-infringement lawsuit, filed in U.S. District Court in Atlanta, seeks an injunction and unspecified damages against the network. King delivered the speech in the late summer of 1963 before 200,000 people in Washington. CBS, a unit of Pittsburgh-based Westinghouse Electric Corp., filmed the speech as part of its news coverage and today sells the tapes commercially. King registered a copyright on the speech, the estate claims. CBS News President Andrew Heyward said the company isn't required to seek permission before distributing news material.