Turn off the 3G when you're in areas without full 3G coverage, it will fix your problems.
whats the point of the hassle when we have 3G AND pay for it? yes, that may fix the problem for him but he still has to pay for it. Apple has told me several times to do this for my dropped calls as well. i told them i "will not" do that. i bought a "3G" and "pay" for 3G. if i wanted less, i would not be on the phone.