About Google Analytics

http://www.google.com/support/googleanalytics/bin/topic.py?topic=10977

Installing the tracking code

http://www.google.com/support/googleanalytics/bin/topic.py?topic=10976

How do I add tracking code to my website?

http://www.google.com/support/googleanalytics/bin/answer.py?answer=55488&topic=11126

You can implement the JS on a couple of test pages if you would like to

test the result before including it in all your pages.