Pandora has finally announced a new on-demand music service called Pandora Premium. The new on-demand service, which costs $9.99 monthly, offers a combination of radio-like listening as well as the option to search and play any track and create your own playlists. Currently, Pandora's Internet radio can be listened to free with advertisements, but you cannot choose a specific song, only artists or a type of music. Pandora Premium is rolling out starting this week via invitation.