Digital music provider Puretracks unveiled a DRM-free mobile music service designed specifically for BlackBerry smartphones, and includes content from all the major music labels.

The company is previewing the device at the SXSW event this week, with a live launch planned for the CTIA Wireless conference April 1. It will roll out first in the U.S., followed by Canada and other markets in the months that follow.

Still unknown is the breadth of catalog available at launch. While Puretracks has relationships with all the major music labels, and several indies, for its online store and white-label services, it's not clear the full catalog will be available on the coming mobile effort.