Hello David. Pls is for Playlist file. You need winamp (http://www.winamp.com) or Real Player (http://www.real.com) . Both are free.
After installing one of them, just click on the .pls link or copy/past it into your player in 'Open a url' menu. Hope it helps you. Thanks for your interest. -- Dimitri Pike http://wildtek.free.fr http://wildtek.blogspot.com http://groups.msn.com/313TechnoMusic