THE INSTRUMENT RATED PRIVATE PILOT DEPARTED ON A NIGHT IFR CROSS COUNTRY FLIGHT INTO FORECASTED ICING CONDITIONS. DURING THE APPROACH AT HIS DESTINATION AIRPORT, THE PILOT REQUESTED LOWER ALTITUDE TO ATTEMPT TO BREAKOUT FROM THE WEATHER. AFTER BEING ASSIGNED 3,100 FEET AND OBTAINING A CLEARANCE FOR THE ILS APPROACH, THE PILOT CANCELLED IFR DURING DESCENT AND PROCEEDED VISUALLY FOR THE AIRPORT. THE AIRCRAFT OPERATED IN AN AREA OF REPORTED FREEZING RAIN AND ICE PELLETS, WITH FOG AND DRIZZLE. CONTROL WAS LOST DURING THE TURN FROM BASE TO FINAL APPROACH.