The "bretteleben.de Google Ad Manager Plugin" and the "bretteleben.de Google Ad Manager Module", both for Joomla 1.5, allow you to use the Google Ad Manager with Joomla. The plugin has to be installed and activated, it does the real work. Besides, it allows you to publish Ads, deliverd by the Google Ad Manager within content items. The module allows to display Ads, deliverd by the Google Ad Manager in module-positions.