Research In Motion is working on a music service that will tie in with BlackBerry Messenger. CNET reports that RIM will deploy a test version of its subscription-based streaming music service in the coming weeks, and that a final product will come later. BlackBerry owners will be able to share their songs with other subscribers using RIM’s BBM service, the report suggests. It’s unclear how much the BlackBerry maker plans to charge, but The Wall Street Journal said it will cost “significantly less” than similar services such as Rhapsody and Spotify, which both charge about $10 per month for premium access. RIM has already inked deals with Sony Music Entertainment, Warner Music Group, EMI and Universal Music to provide the content, according to reports.