TechCrunch reports cross-platform radio station Slacker raised $3 million in debt funding , according to an SEC filing. The company hasn’t disclosed too many details about the investment, aside from a confirmation that it has secured capital from all its existing investors. Slacker also said the sum will be used “for scaling the business” based on a solid business model it recognized in 2010.

“Pressed, a spokesperson would only say that Slacker has identified a solid business model in 2010 (perhaps the one Michael Arrington deemed ‘not quite a scam but close’?), and that it would be ‘leveraging mobile and automotive relationships’ this year.”

Slacker has plans to partner with carmakers to expand its turf even further, which currently includes apps for BlackBerry, iOS, Android, webOS and Windows Phone 7 as well as other and web-based versions. Moreover, a music-on-demand offering is expected to debut soon.

Slacker is not just trying to expand its’ offerings spread, but also its user base and demographics. The company launched 4 new Latin stations yesterday: Regional Mexican, Spanish Pop, Reggeaton/HipHop and Rock Alternativo, all programmed by industry veterans Alex Cortez and Jackie Madrigal.

The Latino demographic is a growing one in the mobile space, more notably in the entertainment segment. SiliconANGLE covered the Millennial Media SMART report indicating the Hispanic demographic leads mobile usage, making it a group ripe for mobile marketing in many regards.  In other mobile music news, we’ve heard circling rumors of Spotify’s US debut, and an update from competitor Last.fm, now charging subscription fees for mobile and remote device streaming.