Google Analytics Input, a simple and effective plugin for adding your google analytics code into wordpress which doesn't track admin users.
Login to google analytics, go to the website profile which you want, edit and go to check status and there you see your google analytics code. You just want to copy your google analytics ID which will look like this UA-0000000-0 (but will be your own unique id.)
No, you wouldn't want to track logged in users because this would give you invalid results, everything else is tracked.
It should work from 2.6 upwards.. Has been tested on all current versions and is working.