Hi Craig,
It's odd that you are getting double vertical scroll bars in IE8 using overflow - that behaviour was part of (lte) IE7 browsers but was supposed to be fixed for IE8. Are you looking at your page in IE8 in compatibility view?
Your page - without using overflow - is working fine for me in IE and Firefox, with the footer at the bottom of the page but moving down as it should when the content is greater than the screen height, and I can't seem to replicate the problem you are having.
[I also have 1920 x 1200 resolution and tested at the resolutions you specified]