How does a user delete a post?

Now that my site is open [thanks for all your help making that possible], my users are bringing up problems i didn't think about.

How does a registered user delete a post they made? In the course of getting used to the site, people have posted "tests" trying to see how everything works. Once they figure it out, they want to delete the post. There doesn't seem to be anyway for them to do it now. These are original posts or replies to posts. I thought the permissions would already permit them to delete since they are the author.

Any help you can provide/settings you can fix will be appreciated.

Mark