The service, which costs $49.99 annually (or $14.99 quarterly) boasts over 3.5 million songs in "ad-free, high-fidelity streaming audio." There are over 100,000 channels that, according Mercora, are searchable by artist, genre, and subgenre.

Mecora also allows you to access your music library on your PC, or optionally on Mercora servers, requiring no side-loading or synchronization. You may also listen to music, playlists, and listening histories from up to five "friends and family."

Sound files are optimized versions of the open-source Ogg/Vorbis audio codec. Support for the A2DP Stereo Bluetooth profile means music can be played back wirelessly over a smartphone's Bluetooth connection; so you can listen on wireless stereo headsets, in-car, or through in-house connections.

The Mercora M music subscription service is compatible with Windows Mobile 5.0 Smartphones and Pocket PCs and Windows Mobile 2003 SE devices. It requires an EDGE, EV-DO, UMTS or HSDPA cellular-wireless data connection. And, as with all services that require the heavy exchange of data over a cellular connection, we highly recommend you’ve signed up for an unlimited data plan with your mobile operator.

SmartPhoneToday Staff contributed to this story.