http://www.youtube.com/watch?v=l7simZEwuk8
i do this as described in the Card Classics of Ken Krenzel. what i do is push the card in with an angle jog so that the inner left corner moves to the right of my right thumb, sticking out the back of the deck. Then, like a diagonal palm shift, i pivot the card around my right thumb using my left pinky just enough so that my left index finger can straddle grip the card. Since it is already clear of the right thumb, the left fingers (in straddle grip) just strip the card out and backwards as i lift the deck with my right fingers to dribble. Just work on the timing so that the noise of the card being pulled out blends into the sound of the dribble, and remember, you dont need hardly any clearance, just enough for the first card being dribbled to land on top of the selected card, then gravity will take over. Because you were already in a straddle grip position, you wont have to adjust your fingers at all while catching the dribbled cards.