Confusion reigned when an Aerostar pilot started to cross a runway as cleared only to receive an undirected radio transmission of 'stop; stop; stop!' A minor technical conflict occurred between the reporter's aircraft and another landing at the far end of the mile long runway.

Narrative

Ground gave me the following clearance to taxi; 'expedite taxi; jet traffic on Charlie. Taxi Charlie and Alpha. Cross Runway XX.' I repeated the instructions and taxied onto Charlie in front of the distant jet taxiing about a quarter mile behind me. I crossed the Runway XX hold line. Ground had been quiet since my reply. Suddenly the words STOP; STOP were heard. I stopped the plane before reaching the edge of Runway XX. I looked to the right and saw a Cessna 182 at the other end (East end) on short final for Runway XX. The Cessna completed his landing and exited the runway about half way down the 5;000 FT runway.There was no other transmission on Ground frequency after the word STOP for a few minutes. Then the Cessna was given taxi instructions. Then the Ground Controller instructed me to cross Runway XX; right on Alpha; which I did. No mention was made by the Controller about stopping so I do not know if the Controller said STOP or the pilot of another airplane (the jet?) on the frequency said STOP. However; I did verify with my passenger in the right seat; an avionics technician who was there to document performance of some new avionics; that I was cleared to cross Runway XX. In my judgment; had I continued to cross Runway XX and not stopped I would have been well clear of the runway before the Cessna touched down at the other end. Furthermore; the voice that said STOP; STOP did not sound like the Ground Controllers voice.