That is a musical, but the rights to the story were out of copyright, so I'm pretty sure Lloyd Webber didn't have to buy any rights. Yeston is also the composer of "Titanic: a New Broadway Musical"... which actually isn't new anymore, and isn't even on Broadway. Anyway... the soundtrack for "Phantom" can be found here...
Phantom - Maury YestonIt stars Richard White (the voice of Gaston in Disney's Beauty and the Beast) as the Phantom and Glory Crampton as Christine. It is based on a made-for-TV-movie released in two parts, found on DVD here:
The Phantom of the Opera - TV MiniseriesIt stars Charles Dance as the Phantom, Teri Polo as Christine, and Burt Lancaster in a surprise part.