PowerResizer

PowerResizer is a utility that provides many facilities in moving or resizing windows in a Microsoft Windows desktop environment. One of the key-features of PowerResizer is window-docking: with PowerResizer you can organize your window in an intelligent way. Try the following: run PowerResizer, then dock a window in the left-half of your screen (simply dragging-it with your mouse to the left of your screen) and another window in the right-half; now you can resize them using either the left border of the right window or the right border of the left window... the magic happens!