2000 Hyundai Accent How do I remove the pulley?

2000 Hyundai Accent mileage: 100,000. I am replacing the timing belt. I have all the parts out of the way except for the crankshaft pulley. How do I remove the pulley? There is hardly any room to work with. I have tried to remove the center nut on the pulley with no luck. Each time I try to loosen it, the engine turns over. Any help would be appreciated.