Tell them.
You'd be suprised how cool most cops are. You're only SOL if you get the guy while he's training with his FTO. I also hand the CCW and the license at the same time, CCW on top. I try to have it out by the time he gets to the window. If not, and he aproaches the window, I mention that I have a CCW and it is on my right hip under my shirt. All while having my hands on the wheel open palmed, interior light on, and all windows rolled down, engine and radio off. Seat belt on.
If he asks you to get out of the car, let him know that you've got to reach over and unbuckle your seat belt. Once out of the car, NEVER stick your hands in your pocket, don't cross your arms, don't put your arms behind your back either. They'll usually take you to the back of your car, or have you put your hands on their bumper. Don't remove them.
If they ask you to give them your gun, draw it slowly with the muzzle pointed at the deck, bring in front of you, grasp slide with opposite hand and present it to them that way.They'll ususally want to unload it themselves.
When they first aproach the car, and you don't have your license out; await instructions after informing them that you have a CCW. If you say, "I got a gun," and start digging for your wallet, everyones asshole puckers.
-Steve