FireFly Mobile, a pay-as-you-go mobile service for the tween set, is prepping a mobile music service. The company is looking to offer more than 2 million "age appropriate" tracks for its 8-12-year-old target market.

It tapped PassAlong Networks to provide the service via the StoreBlocks digital distribution platform.

No details were provided about when the service will go live, how much each track will cost, or which labels are participating. But it does plan to focus on DRM-free MP3s rather than protected tracks.