At about 1630 eastern time, a Cessna 210E caught fire while standing after engine start at the Tallahassee Regional Airport. No one was injured. The pilot said he started the engine and was reading back an instrument clearance when fire was observed coming from the engine compartment. The pilot and two passengers evacuated safely. Moments later, the fire department arrived and extinguished the fire. Examination revealed there was a fuel leak in the engine compartment.