Don, just created a test ad with my regular user account to test. -you should see a 'edit this listing' link near the top of you full page listing along with a 'delete listing' button. Also, there should be a 'Delete' text link at the bottom of your ad only you can see. The AD owner only sees these links.
If you still can't find the links, list the ads you want deleted here.. we get it for you.
Scott