A free app for Windows, by Nurgo Software.

AquaSnap is a very powerful utility for the desktop which allows you to easily resize your windows. You can resize them by just dragging and dropping them anywhere on your screen. 

AquaSnap is extremely easy to use. You can easily customize the UI of your screen to give you the interface you prefer. The app has many options to allow you to resize a single window or all of your windows at once. 

AquaSnap is a very powerful utility that can be used as an alternative to more expensive programs Aero Snap and Aero Shake features of Windows 7.