If you are interested in evening out tire wear on the street, I suggest buying a tire depth gauge. They inexpensive and available at any auto parts store.
Then measure the tread depth at various points across the tire every thousand miles or so.
If you notice the rears are wearing faster in the center than on the edges, lower the pressure several PSI. If the edges start to wear faster, raise the pressure a little.
After you do this a few times you should get a feel for what pressure matches up best to your driving style for evening out tread wear.
If you decide you don't like the way the car handles with the lower pressure just go back to stock. The average driver probably won't be able to tell the difference.
[This message has been edited by Lud (edited 05 July 2002).]