[web] CSS Layout - Fluid Width

Hi all, I've been trying for a while to get a particular layout to work correctly, but I havn't been able to find any solutions myself, and have been unable to locate any solutions elsewhere either. Basically, I've got a number of divs being used to position content. For simplicities sake, I'll just talk about two for now. I have them layed out something like the following:

+---------------------------------------------------+
|+------------++-----------------------------------+|
|| FIXED      || NON-FIXED WIDTH DIV               ||
|| WIDTH DIV  ||                                   ||
|+------------++-----------------------------------+|
|           REMAINING SPACE IN BROWSER              |
|                                                   |
+---------------------------------------------------+

Now, as that hopefully shows, I've got a fixed width div floated to the left, it's sitting in the upper-left corner of the browser window. Sitting next to that I have another div, with a non-fixed width. I'm trying to get this non-fixed width div to expand to fill all the remaining space, but have been unable to do so thus far. I don't want to fix the width. Setting the width to a % takes it's value from the container if I'm not mistaken, which results in the (correct but undesired) behavior of it being pushed down below the fixed-width and expanding to fill the browser. So, does anyone know of a solution, or have any ideas where I could look? I'm also going to be a bit of a pain in the a$$ and say I'd like to support as many browsers as possible correctly (at least Opera, Firefox, and IE), and that &#106avascript should be avoided if possible (if there's no other way I'll probably use &#106avascript to calculate an appropriate fixed width instead).