Read up a little on Maximizer. You can basically set it to carve your monitor in 1/2 and you'll be able to utilize every pixel of your screen...

I know Maximizer has been talked to death, but a short rundown is this:

Put maximizer in your WoW directory. When you run it, it calls the WoW.exe file.

Command to start it is something like this:

[code:1]maximizer.exe --margin 0,0,0,800[/code:1]

The four numeric values are the the number of pixels from an edge to have this session run. The are in the order: Top, Bottom, Left, Right. So my example says "from the very top to the very bottom, From the very left to 800 pixels from the right edge."

If you have a 1600x1200 screen, that'll fill the left side with a WoW session.

For your second session, start Maximizer like this:

[code:1]maximizer.exe --margin 0,0,800,0[/code:1]

That should carve your screen basically in half with two WoW sessions...

You can also put the margin settings in the maximizer.ini file... Hope that helps.