C182 Jump Pilot experiences an engine failure during descent over the departure airport and lands safely.

Narrative

Flying skydivers from airport to 10;000 FT directly above the airport. Upon the fifth load; which had one more person than the previous loads; thus causing a longer flight time to 10;000 FT. Upon divers jumping on the fifth load; I began my slow descent back down to the airport. At about 5;000 FT on the descent engine started surging; so I leveled off and added mixture and carb heat; temporarily fixing the problem. Upon reaching about 3;000 FT total power was lost; after multiple attempts to fix the problem; I simply accepted the fact that I would have to execute an engine out landing; which was uneventful. I'm not 100% sure what the problem was; but the fuel was lower than normal when I added fuel; and since we spiraled down to get down faster fuel may have had a hard time getting to the engine; and the spark plugs on that plane had been fouling really badly on the descent all day long; causing long run ups to clear the plugs. The important thing is that the problem was recognized; the corrective actions were taken; and calmness was maintained throughout and after the situation occurred.