NEW YORK     Def Jam Records, a new independent label specializing in rap music, is being started by Run-D.M.C. manager/producer Russell Simmons and producer Rick Rubin
     "The purpose of this company is to educate people to real street music by putting out records nobody in the industry would distribute but us," says Simmons
     The first single on the Malverne-distributed label L.L. Kool J's "I Need a Beat." Also on the roster are Run-D.M.C. spinner Jazzy Jay, who will have a single titled "Def Jam"; TLA Rock, whose Rubin-produced 12 inch, "It's Yours," was an underground rap favorite last summer; Jimmy Spicer, who has previously recorded for Spring; and the Beastie Boys, a group of white rockers who rap over heavy metal rhythms.