A STUDENT PLT IN A CESSNA 152, N5522L, HAD DEPTD REDBIRD ARPT AT DALLAS. HE WAS PRACTICING SOLO MANEUVERS IN A PRIVATELYDESIGNATED PRACTICE AREA THAT OVERLAPPED THE EXTENDED INBND COURSE TO RWYS 31L & R AT LOVE FIELD. AT THE SAME TIME, A CESSNA 441, N400BG, WAS BEING VECTORED FOR A BACK COURSE ILS TO RWY 31R. DFW APCH CONTROL CLEARED N400BG TO CONT DSCNDG TO 3000' & FLY HDG 290 DEG. WHILE N400BG WAS DSCNDG THRU APRX 3600', ABOUT 14 MI SE OF LOVE FIELD, THE 2 ACFT COLLIDED. THE CESSNA 152 PLT WAS MANEUVERING AT OR NEAR THE EDGE OF THE PRACTICE AREA WHEN THE COLLISION OCCURRED. AN INV REVEALEDTHE CESSNA 152 HAD JUST COMPLETED AN APRX 180 DEG TURN TWD AN EASTERLY HDG. BOTH ACFT WERE DEMOLISHED IN A QUARTERING HEAD-ON COLLISION. RADAR INFO FM BOTH ACFT WAS DISPLAYED ON THE CONTROLLER'S SCOPE. THE CESSNA 152 WAS DEPICTED AS A 1200 BEACON CODE; HOWEVER, IT WAS NOT EQUIPPED WITH A MODE C (ALT RPRTG) TRANSPONDER. THE CONTROLLER DID NOT PROVIDE A TRAFFIC ADVISORY FOR THE CESSNA 441 PLT; BUT, IN THIS SITUATION, AN ADVISORY WAS NOT MANDATORY.