If you've linked your Blogger account to an approved AdSense account, you can use AdSense to monetize your own site. To do this, you need to add the site to your sites list. AdSense will review your site and let you know when it's ready to show ads. You can then set up ads on your site.
If your blog qualifies for AdSense but you haven't signed up yet, see: Advertise on your blog.
