[thelist] Tricky CSS positioning

I'm in the process of rewriting a large site so that we have a table-layout
version and a CSS-layout version (all the detection will be server side, so
the extra code won't be a burden), and I find that my CSS knowledge is a bit
hampered by the browser compatibility issues we've all been dealing with --
I can do style sheets for font control with my eyes closed, but some of the
dynamic positioning is all new.

So, the question is: they layout that I'm working with is based on a
four-sided box with content dumped into the middle.  With tables, it was
coded without fixed width so that all the "box" elements resized with the
browser window.  Using style sheets, I've got the left, top and bottom
working (although the bottom needs work), but I'm in over my head trying to
make the right hand bars of color (previously table cells) move properly
with window resize.  This has to work for IE4+ win, and I'd like it to work
for NN4+ as well, but that's not absolutely necessary.  I can always give in
and do a table, but I'd rather do it right (especially since I've been
begging for a chance to fix the site for months now).

Help?

thanks-
Erin