AND WAIT, THERE'S MORE: How's this for an odd couple--Run-D.M.C. and Aerosmith? The heavy-rappers and the hard-rockers have teamed up for a remake of Aerosmith's "Walk This Way," which will be on Run-D.M.C.'s new album, "Raising Hell," due out in early May. The unusual collaboration features the Run-D.M.C. crew, with vocals and guitar flash by Aerosmith's Steven Tyler and Joe Perry, respectively. . . . Alex Chilton has a three-song EP due out this month featuring such songs as "No Sex" and "Underclass."