Yahoo is struggling with some tough decisions right now, and everyone has seen both Microsoft and Google sneak in and prepare to gobble up the company. Yahoo is still operating at full speed though, and as part of the fallout from falling profits they have decided to axe Yahoo Music. Rather than cutting their customers off completely - which would have been a PR disaster - they are redirecting them over to Rhapsody as part of an agreement between Real Networks and Yahoo.
The transition will happen fairly soon, and supposedly customers making the switch will still have the same subscription fees they do now - at least for the near future. Eventually however those former Yahoo customers will have to get new accounts with Rhapsody and presumably will lose access to content bought from Yahoo if the person does not sign up with Real Networks. An interesting point, especially since the head of Yahoo Music said only a year ago that he was opposed to DRM and wanted more flexible services for people.