WordPress.org

1. Log in to WordPress as an administrator
2. Go to Plugins > Add New and search for wp-TrackbackPopup
3. Click install next to the wp-TrackbackPopup plugin description
4. Click the Install Now button in the pop-up window
5. After the plugin is installed, click the Activate Plugin link
6. Go to Settings > wp-TrackbackPopup to set your preferences

Alternately, you may manually upload the plugin by following the following instructions:

1. Go to http://wordpress.org/extend/plugins/wp-trackbackpopup/, and click the Download button
2. Unzip the wp-trackbackpopup.x.x.zip file
3. Using your favored FTP client, upload the wp-trackbackpopup folder to the /wp-content/plugins/ directory
4. Log in to WordPress as an administrator
5. Go to Plugins > Installed, locate the plugin and click the related Activate link.
6. Go to Settings > wp-TrackbackPopup to set your preferences