Verizon Wireless today introduced Rhapsody's subscription music service, allowing its customers to download as much music as they want to their phones for $15 per month. Rhapsody is following in the tracks of Napster, Apple's iTunes and Amazon.com, all of which have introduced MP3 downloads and moved away from digital rights management, or DRM, which prevents copying and piracy, but also makes it difficult to legally move music between devices. Rhapsody also provides 30-second music samples that...