I agree with spatts on this- I keep the bar over the wrist, on the lower "meaty portion" of the palm. I have never had to do any strengthing exercises and it does cause a slight angle in the wrist, which from habit, I just kind of lock in. Also, I rarely have wrist problems, though I do get a little callousing and bruising on my palm (lower hand, away from normal callouses up bythe fingers) from time to time....
I think the key is envisioning the elbow, wrist, and bar all in line vertically..