Hydra: A lightweight OS X window manager with a powerful API
If you're looking for a window manager for OSX without having to actually configure anything, you can try using Spectacle: http://spectacleapp.com/For instance on my imac 27'' I have Option+Command+Left|Right keys mapped to side (similar to windows 7.And I can also have 4 windows open at once using Shift+Option+Command+Up|Down|Left|Right to move them to the different corners. Works really well with less than 2 minutes of setting the hotkey on a simple GUI configuration window.