MediaChance has released a free application for dual and triple monitor users. To boil this program down it simply puts a taskbar on your 2nd or 3rd screen. MultiMonitor will show the applications that are open on only that monitor. A couple of extra bonus features are a clipboard extender that shows up in the lower right of your 2nd display. There is also a button near your minimize button that can automatically move your windows to your primary or secondary display.
Windows only and totally free