Keyboard shortcut for current window position

I am looking for the keyboard shortcut to place the current window in half of the screen, either to the left or right. This functionality is performed in windows by typing the windows button plus left or right.

How is this done on Mac OSX?

Slate is an extremely customizable keyboard window management tool. It can take a while to get setup (although there are some example configs) but it's totally worth it.

Edit:

Slate has seemly abandoned at this point. I have switched to Phoenix which is very similar and more actively developed.

I use Divvy to perform keyboard manipulation of window size. There is a free demo so you can try before you buy.

If you want to build your own keyboard shortcut here is how you do it:

1. Open Automator (Applications > Automator)
2. Make a new Service
3. In the search pane on the right search for "Applescript"
4. Drag "Run Applescript" into the right Pane

5. In the Text Box that is presented enter the following code:

   on run
       set theApp to ((path to frontmost application) as text)
       tell application theApp
           activate
           set the bounds of the first window to {0, 0, 1280, 800}
       end tell
   end run
   

6. At the top of the right pane make it so that the service receives no input

7. Save the service as "Maximise Window"
8. Duplicate the Service (Command + Shift + S)
9. Change the {0, 0, 1280, 800} to {0, 0, 640, 800}
10. Save the service as "Move Window Left"
11. Duplicate the Service (Command + Shift + S)
12. Change the {0, 0, 640, 800} to {640, 0, 1280, 800}
13. Save the service as "Move Window Right"
14. Go to System Preferences (Applications > System Preferences) and select "Keyboard" then "Shortcuts"
15. Scroll down in the list to "General"
16. You services should be saved there. Hover over them then add your own shortcuts.

And Done!