Thumbplay is adding content from 20 new licensing partners for its new on-demand streaming music service, Thumbplay Music.

The company launched the service as an invite-only beta last month with content from the four major record labels. New content partners now include Beggars Group, Redeye Distribution, TuneCore, IRIS and a number of other independent labels. The new deals bring the number of tracks available to stream on demand to 8 million.

Thumbplay says it will offer a three-day free trial period of the app once it's released for public availability, and then charge $10 a month thereafter. It initially is available only on BlackBerry phones, but plans to extend to the iPhone and Android devices in the near future.