Fedora 9, Gnome.

I'm running a Radeon 3870, and am having a bit of trouble getting two
desktops running on two LCD monitors. I'm wondering if someone can
give some advice or point me to a how-to (that works).

So far I'm able to get the same desktop to show up on both LCD
monitors, one is natively 1900x1200, the other is 1280x1024. However,
on the 1280x1024, it only shows a small portion of the desktop, it
reports it's running at 738x414 (no idea how it picked that).

Is there some "utility" that I can use to aid in this task? I don't
want spanning, I prefer to have two separate desktops.