This code snippet will force your ie6 clients to understand min-width, pretty cool hack.
element.style{ _width:expression(((document.compatMode && document.compatMode=='CSS1Compat') ? document.documentElement.clientWidth : document.body.clientWidth) < 660 ? "660px" : "auto"); }
Note that I prepend '_' before 'width', that ensures that only ie6 will bother to try to interpret that command, other normal browsers will ignore that.