Mobile music specialist mSpot has inked a deal with Sony Music Entertainment to add the record label's catalog to its customizable ringtone offering.

Available through AT&T, Sprint and Verizon Wireless, mSpot's Make-UR-Tones lets users create their own original ringtone from any of more than 400,000 full tracks.

With Sony on board, mSpot now has tracks from all four major label groups as part of Make-UR-Tones. The service also includes tunes from indie labels INgrooves and IRIS.

At the end of 2008, mSpot topped four million subscribers, a 260% increase over '07.