css q: scrolling central text with header and footer

A problem I am puzzling with:
I would like a page with a header (stuck to the top of the browser
window, say 50px high), and a footer (stuck to the bottom, also 50px).
Between these there is text, which sometimes may be too much for the
available space (between header and footer. So I'd like the scroll bar
to appear then.
I've had it all working at some stage in Firebox, but it would not
work properly in IE (due to 'bug' in IE).
I know "Overflow: auto;" is used to get the scroll bar to appear in
the box, but the problem is the margins I set to this box - the box
wants appear below the footer.

Any assistance appreciated.

Rob