EdgeSwap is simple portable task switcher which allows to switch between opened windows very easily.All user need to do is place mouse cursor on left hand corner of screen to switch between Windows, hold your mouse cursor on edge until your desired window is highlighted on the popup, then move the cursor away from the edge for the window to open.
In Windows 7 and Vista EdgeSwap shows live thumbnails images to switch between windows , where as in XP it shows icons of opened windows much like in pressing Alt+Tab does as below.
EdgeSwap is freeware and portable,no installation required.