You have to set iTunes as your default mp3 player. You can do this in iTunes. Open iTuens, go to Preferences, Click the General tab, and click Set for Use iTunes for Internet Playback. Then when you use Limewire, you can just double click a completed file either in the Search window or in the Library and it will play in iTunes automatically, as well as automatically adding the file to your Library. Be sure you have deselected the Limewire player in your Limewire Preferences.