RealNetworks (NSDQ: RNWK), among the early proponents on DRM-free music, has finally been able to launch an MP3 store, joining the likes of Wal-Mart (NYSE: WMT), Amazon (NSDQ: AMZN), Napster (NSDQ: NAPS) and iTunes, who have started offering a range of MP3 options over the last year. Rhapsody’s MP3 store offers music from all four major labels, with singles at the usual 99 cents price, and most albums priced at $9.99. The service is now a joint venture between RNWK and MTV Network, who joined together last year to form Rhapsody America.

Along with this launch, Verizon Wireless (NYSE: VZ) is also introducing Rhapsody’s on its mobiles, allowing users download unlimited music on their phones for $15 per month..this is a sideloading service, meaning users will have to download on PC and then sync to their Verizon phone. The dual delivery songs will have two forms: the online/PC one will be MP3, which can then be tranferred to the phone as is, but if a song is downloaded over-the-air on the phone directly, it will be be in a DRM-version, according to this AP story.

Rhapsody is also finally being integrated within MTVN’s (NYSE: VIA) sites: Rhapsody-powered music playback (full songs) and MP3 purchasing options will be available as widgets within MTV, CMT, and VH1’s websites. A $50 million marketing campaign, in conjunction with MTV, will also begin immediately.

News.com: While Rhapsody’s MP3 pricing is competitive with iTunes, it’s slightly more expensive than Amazon, and considerably more expensive than eMusic. As a competitive advantage, Rhapsody’s new online music store allows users to preview entire songs prior to purchase--a stark contrast to the 30-second song previews shoppers have come to expect.