There have been conversations in the Forum regarding proper air pressure vs. load. In researching tire data for my Hankook Dynapro AT2's, I came across this cool site. It doesn't recommend pressure for a specific load, but it does have other good information including a calculator for the effect of temperature change on pressure - the good old ideal gas law (P1/T1=P2/T2).
TIRE PRESSURE SITE
EDIT: By golly, it does have recommended pressure for a given load.
I hope it helps!