THE STUDENT PILOT WAS ABOUT 47 MILES FROM HOME AND NEARING COMPLETION OF A X-C FLT WITH HIS WIFE, FATHER, AND MOTHER. THE PLT HAD REQSTED VFR FLIGHT FOLLOWING & HAD BEEN CRUISING AT 6500 FT. THE PLT ADVISED ATC THEY WERE DOWN TO 6250 FT & NEEDED TO DESCEND FURTHER TO REMAIN VFR. ATC ADVISED THE FLT THERE WAS OPPOSITE IFR TRAFFIC WHO HAD ADVISED HE WAS 'IN SOLID' & REQSTED THE VFR FLT TO DELAY DESCENT IF POSSIBLE UNTIL TRAFFIC WAS CLEAR. THE PLT AGREED BUT SAID 'WELL OK, I'M GOING TO BE IN THE CLDS.' ABOUT 45 SECS LATER, THE PLT ADVISED, 'OH YEAH, WE'RE WE'RE IN A SPIN, I'M NOT SURE WHICH WAY WE'RE GOIN' HERE, I'VE LOST IT, I'M SORRY. ' A GRND WITNESS HEARD THE ENGINE REV UP IN THE CLDS, LOOKED UP & SAW THE FUSELAGE MINUS WINGS & TAIL SPINNING FROM OVRCST. THE WITNESS SAID VFR CONDTNS PREVAILED AT GRND LEVEL. THE PLT HAD OWNED ACFT ABOUT 2 YRS BUT NEVER REGSTED IT & THERE WAS NO ANNUAL INSP PERFORMED. NO PLT OR ACFT LOGBOOKS WERE FOUND.