spooky for Mac

From Mindwarp:

Spooky is an AppleScript, designed to give you the ability to handle front window size and position with your keyboard. You can maximize your front window to full screen or just to the sides or the edges of the screen. You can move your front window to the sides or the edges of the screen or center it on the screen. Furthermore you can grow or shrink your front window size to some special values. The next smaller or bigger size of 640x480, 800x600, 1024x768 etc. will be choosen. You can set the ratio manually to any value you like. In Addition you can set a margin so that the windows won't fill the screen till its border. If your dock is visible, its space will be reserved.