Take a look at the Safepacker.
From Wilderness Tactical. Great little set up. You can thread the seat belt through it instead of putting the gun in the door pocket.
They have pics on their website. The advantage to this over the door pocket is that you will be reminded to take your weapon with you when you unbuckle and if a carjacker opens your door your weapon wont be out of reach.
I pocket carry on occassion and came to realize that I'd never be able to get to my pistol quickly. I've been trying to decide between the Safepacker and one of Tommy's Pistol Packs now.
Off the body carry has some advantages but it takes some getting used to.