Whenever you reference an older post in your blog with the help of a link, WordPress send a ping back and a link shows up in the comment field

Some people really like that WordPress sends pings from your own site to your own site when you write posts. It gives them a trail of related posts,  and some do not like this behavior as it clutters up their comments and becomes an issue when you have a lot of self pings

No self ping WordPress plugin disables pinging your own blog and disables showing track backs in the comments field

For installing this plugin, you can refer my earlier post on how to install a plugin from your admin panel

You can also download this plugin from WordPress Plugin directory by clicking here