2Up by Irradiated Software is a very basic tool that I use every day. 2Up allows you to simply tile windows across the screen. This is a feature that is built into Windows 7, but has been left out of OS X for some reason. For those of you that don’t know what I mean by title windows, it is the ability to divide your screen relestate evenly by multiple windows, hince allowing you to view multiple windows. Well, with OS X, to do this, you have to maunelly resize the windows and drag them into place. With 2Up, you simply use a menu bar drop down, or a nice quick keyboard shortcut.
How 2Up works, is you install it on your computer. Once installed it run very quietly in the background. When you need to split screen 2 windows, you simply use ⌘ + ⌥ + ∧ and arrow key depending on where your want the window to appear. i.e. If I want my Google Docs to fill the right half of my screen, I simply open the window and click ⌘ + ⌥ + ∧ + right arrow, then if I want my Tweetdeck on the left side of my screen, I simply open the window and click ⌘ + ⌥ + ∧ + left arrow. This works with up and down also which is great when coding in HTML or PHP.
I highly recommend this application, it is simple, light system footprint, and free. It will also help you to increase your productivity level.