Strike, here is a drill that Ron Clifton had me do when he was teaching me different releases.
Before starting try this strength test. Pick up your ball, let it dangle at your side, point your finger towards the floor. Cup your wrist for a slow 10 count, if your hand falls flat, or you can't maintain the wrist position, then your wrist isn't strong enough, and you should try to build up the strength in your wrist before trying this again or you run the risk of hurting yourself.
If you aren't strong enough and would like to learn more on Bowling Specific Training, you can pruchase the only manual written on the subject by Dr. Jeff Briggs
http://webpages.charter.net/bowlfit/manual/. It is a great book and I would highly recommend it to anyone looking to improve their game.
If you can hold the ball for a 10 count, then you are ready to try this.
Get your ball, go to the foul line and get in position to release the ball, (knees bent, sliding foot at the foul line, non sliding foot behind you).
Put your hand in the ball and let it dangle at your side.
Place your hand in what ever release position you are trying to achive, in this case point your index finger toward the floor and keep your pinky close to your ring finger, and cup and cock your fingers toward your sliding ankle, like you were grabbing a round door knob.
Keeping your hand in this position, swing the ball back and forth a couple of times to build momentum and get the feel of your hand staying in this position until you release the ball.
After swinging the ball several times, tell your self to turn the ball as you release it. Ron referes to it as turning the door knob, because that is the exact movement you are looking for.
Watch the ball the whole time and make sure your hand is in position until the release. Also watch the rotation of the ball and make sure it is rotating the way you want it to after the release.
You can experiment with many different releases and learn many different things with this drill. Just be sure to check your strength before trying this so you don't hurt yourself.