SizeUp [1] (paid but inexpensive) does that well.  They also make a version that uses cursor dragging instead of keyboard shortcuts called Cinch that I use daily. (I really wish they&#x27;d combine the two products for licensing purposes since they&#x27;re 95% the same.)<p>1: <a href="http:&#x2F;&#x2F;www.irradiatedsoftware.com&#x2F;sizeup&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.irradiatedsoftware.com&#x2F;sizeup&#x2F;</a>