Fan bracket, idler, tensioner or a/c compressor. Check and see if the noise comes and goes with the kick on/off of the A/C clutch. If it happens when the A/C clutch locks on it is a sign usually of the compressor going.
If it starts when the clutch kicks off and the Lully starts to free wheel, the clutch bearings are going. Usually spinning the compressor with the belt off will also make any roughness in the clutch bearings obvious.