Moving out of State - Car Registration Due few weeks before the move. Can I register to the state I am moving?

My car is due for a registration renewal plus smog certification on 8-18-09. We are moving out from California to Oklahoma by mid-September, the latest. Can I have the CA registration expire and just register the vehicle in OK? Are there any penalties? How about the PNO option? If I let it expire, how many days would I have until I am in big trouble? Any suggestions will greatly help. Thank you.