Backed by Centennial Ventures, Rho Ventures, Austin Ventures, Mission Ventures and Sevin Rosen Funds, Slacker just got a fresh influx of roughly $3 million in funding this month, per an SEC filing. Cady told VentureWire that the new money came from “inside investors,” serving as a testament to their faith in the company’s mobile-centric future plans.

SEE ALSO: Music Startup Slacker CEO Dennis Mudd Out; $70 Million and Counting

Slacker currently has ad-supported Blackberry and iPhone streaming radio apps; it also offers a desktop-based ad-free service for $3.99 per month. The company will continue to sell the G2 through the first half of 2010; it is not clear how long new and existing buyers will be able to get technical support for their devices after that.

Getting people to pay for streaming radio seems to be hard enough, but Slacker faced the bigger hurdle of going head-to-head with Apple’s iPod, an obstacle that even Microsoft—with what seems like an infinite budget for marketing, promotion and distribution—has found to be insurmountable. Slacker’s 2-gig and 4-gig G2s retail for $199 and $249, respectively—and that’s a tough sell when compared to the 8-gig iPod Nano, which retails for $149, or the 8-gig iTouch, for $199.