My current situation is:

I am only shipping inside the U.S.

I have 7 zones within in the US. Each zone is based on zip code.

There is 3 methods of shipping (ground, ground to P.O. Boxes, and DHL 'rush').

There are 3 categories which determine the % rate of charge for shipping based on zone (orders less than $30, orders between $30-$499.99, and orders $500 and over).

Below is a chart displaying what I have explained above:

<img src="http://i201.photobucket.com/albums/aa108/jamesbarsalou/Untitled-1.gif" border="0" alt="Photobucket">

How can this be executed? Anything will help at this point. Thanks!