lemee get this streight..
u have 2 pages setup like this
| products page | order page | (all in one frames)
when they click on a product on the products page, it shows the order form in the order page?
if this is what you are doing, all you have to do, is when you create the 'order now' link on the products page.. have the target be the order page.. of course the order page will refresh, it has to (in this case) but the products page will stay the same.