Word on the street is that Google has launched an online music store in the US, which is not disimilar to iTunes whereby music fans running the Android software can buy, store and stream MP3 files. Major labels EMI, Sony Music Entertainment, Universal and 23 independent labels are providing content to create a library of 13 million songs.

The service is set to challenge the popularity of iTunes and the iPhone with a new study by the research firm Gartner suggesting that more than half of all smartphones sold between July and September ran Android and this accounts for more than 60 million devices.

Google is also integrating its new service with its Google+ social network so that users will be able to share songs with their Circles contacts who can listen to the full length of the tracks one time without making a purchase. A second play will result in a purchase and songs range in price from 69 cents (44p) to $1.29 (82p) – the tracks will come without DRM copy-protection. The search giant is also offering a different track free for download every day as the firm has secured exclusive content to be able to do so. The rapper Busta Rhymes is debuting his upcoming album on the Android store and The Rolling Stones and Coldplay are offering previously unreleased live performances.

Google is also hoping to link with smaller artists through its new Artist Hub. Musicians can add their own page for a $25 fee and set their own prices. Google will take a 30% share of each sale.

Google did not discuss any plans to offer Google Music outside the US but if you’re a Blackberry user we’re guessing that you heard about Blackberry launching it’s BBM Music service in the UK on Tuesday. The company now offers users 50 DRM-protected tracks of their choice for