iWebTrack provides you with a free downloadable utility that will automatically add the required tracking code to all of your pages for you. Just start it up, tell it what folder your pages are in, and let it fly. The program will automatically insert the tracking code in the appropriate place (right before your </body> tag) in all of the pages in the folder you specify, and subfolders too if you like. The program can add the tracking code to thousands of pages in a matter of minutes - all you'll have to do when it's done is upload them to your web server.
The program also updates older versions of the tracking code and repairs any pages where the code has been modified. Every time you start the application it gets the latest version right from our server, so you'll only have to download it once.