Swap shipping and payment steps?

A client would like to switch the sequence of the shipping and payment steps during checkout. (He frequently gets calls from customers who find the default Zencart sequence confusing.)

Is there a way to make this change? I'm assuming that it will involve editing one or more of the PHP files, which I don't mind doing, as long as it's not too hairy....

Thanks,
Mark

If I understand this correctly - How can one calculate the total to be paid until the shipping method is selected??

If just too many steps you might look in the downloads/other (i think) for the quick checkout module and see if this is more to their liking

I'm looking into this also. My client wants the billing address first, then shipping address, then all the calculations later on. Can anyone help us with this? Surprisingly, said client doesn't want to have a one-step checkout.