**Insert** in your code : to display default ad : ‘< ?php if ( class_exists( ‘MyAdsense’ ) ) MyAdsense::doit(); ?>’ to display ‘name_of_the_ad’ ad : ‘< ?php if ( class_exists( ‘MyAdsense’ ) ) MyAdsense::doit( ‘name_of_the_ad’ ); ?>

http://wordpress.org/extend/plugins/myadsense/installation/