I documented the steps to add AdSense to MediaWiki 1.4, as I suspect others will also find this useful. If you're not familiar with it, AdSense pays you ~70% of the click-though revenues Google receives by placing ads on your page.
http://www.dankohn.com/archives/000338.html
You can see the results at http://www.pwsnotes.org
- dan -- Dan Kohn mailto:dan@dankohn.com