Yesterday, AT&T announced that it was bringing the Pandora experience to the mobile world, staring with eight smartphones: "the Samsung SYNC, a717 and a737, the Motorola V3xx and RAZR 2, LG trax and existing LG CU400 and CU405 models."

Pandora Radio differentiated itself from other online music streaming services through its Music Genome Project, an attempt to create a comprehensive catalog of music. Users first provide their favorite song or artist, and Pandora attempts to create a playlist to suit their musical tastes.

After each song, the user is asked to agree or disagree with Pandora's selection, with the answers helping the service becoming more accurate with every try. It's a win-win proposition: Pandora enjoys massive input that helps it improve itself, while users get to legally listen to music for free.

Much of this functionality is retained in the mobile version of Pandora Radio, meaning that AT&T is now offering a pretty unique mobile music streaming service. Except this time, customers will have to pony up. AT&T subscribers using supported devices can avail of a five-day trial, and pay $9 a month to continue.

AT&T Launches Personalized Radio from Pandora