The mayors of two New Jersey cities and a state legislator were under arrest yesterday, as part of a major corruption and international money-laundering conspiracy probe. Federal prosecutors say about 30 people have been arrested. They include Assemblyman Daniel Van Pelt, Hoboken Mayor Peter Cammarano III, Secaucus Mayor Dennis Elwell and Jersey City Deputy Mayor Leona Beldini. Federal prosecutors say several rabbis in New York and New Jersey were also arrested.