THE ACFT COLLIDED WITH TREES AND TERRAIN DURING A PRACTICE LOCALIZER APPROACH AT NIGHT TO RWY 23 AT BIRMINGHAM MUNICIPALARPT. THE WEATHER WAS VMC AND THE PILOT WAS NOT INSTRUMENT RATED. ON APPROACHING BIRMINGHAM FROM TRI-CITIES, NC THE PILOT ASKED FOR A LOCALIZER APPROACH. HE WAS CLEARED FOR THE APPROACH AND DESCENT TO 3000 FT. AT 1925 WHEN ASKED IF HE WAS RECEIVING THE LOCALIZER HE ANSWERED 'AFFIRMATIVE-ON GLIDE PATH, EXCUSE ME, ON THE CENTER.' HE WAS ADVISED OF HIS POSITION 13 MILES FROM THE ROEBY RADIO BEACON AND CLEARED FOR THE APPROACH. HE ACKNOWLEDGED THE CLEARANCE AND INSTRUCTION TO REMAIN VFR. THE LOCAL CONTROLLER FOLLOWED HIM ON RADAR (NO ALT) AND LOST THE RETURN WHEN THE TARGET WAS 6 MILES FROM THE ARPT. THE CRASH SITE WAS ABOUT ON COURSE NEAR THE CREST OF A 1240 FT MOUNTAIN ABOUT 2 MILES OUTSIDE THEOUTER MARKER. PROCEDURES DICTATE THAT 2000 FT BE MAINTAINED UNTIL INSIDE THE OUTER MARKER. A WITNESS SAW THE ACFT DESCENDING AND HEARD AN INCREASE IN ENGINE NOISE AND SAW THE NOSE OF THE ACFT COME UP BEFORE HITTING THE TREES.