Google has opened a digital music store in a direct challenge to Apple\'s iTunes and Amazon\'s online shop. \"Today we are happy to announce you can buy millions of songs right from Android Market,\" Google product manager Paul Joyce said at a press event in Los Angeles. The Internet search giant synched the music store to its Google Music service, which came out of test mode on Wednesday to become available free of charge to US residents. Digital songs can be purchased online at the Android Market using computer Web browsers, and Google said the service will be rolled out to Android-powered smartphones and tablet computers in coming days. \"Doing a deal with Google for the sale of our repertoire is groundbreaking on a number of levels,\" said Robert Wells, president of global digital business at Universal Music. \"We expect this to be a rich new revenue stream for our artists,\" Wells added while joining music industry peers on-stage at the event. Google signed three of the four major record labels -- Universal, EMI, and Sony Music -- with the holdout being Warner Music, home to Madonna and other artists. Coldplay, Shakira, and the Rolling Stones teamed with Google to celebrate the music store launch by making free or exclusive tracks available. One perk of the new service is the ability to share songs bought at the Android music shop with friends on the Google+ social network for one-time listening. \"Any new legitimate place to consume music is a fantastic antipiracy tool,\" Wells said. Google is weaving in videos from YouTube as the technology colossus combines its widely-used services for better leverage to unseat Apple from its throne in the digital music industry. Google designed the Music Store to allow independent musicians to be able to sell songs at prices of their choosing through an Artist Hub. An unrepresented artist can pay a one-time fee of $25 to set up account and then give Google a 30 percent share of revenue from music sales. \"We think it will be a significant new music destination in the digital space,\" said Merlin chief executive Charles Caldas, whose company specializes in helping independent musicians thrive. Google in May launched a test version of Google Music, which allows users to store personal collections in the Internet \"cloud\" for streaming to smartphones, tablet computers or other gadgets. Google avoided having to cut deals with music labels at the time by letting people store digital versions of songs they already own in online \"lockers\" which they can access using gadgets linked to the Internet. As many as 20,000 songs can be stored at Google Music, which was pitched as \"a completely legal\" service akin to a person storing music collections on home computer hard drives. Google Music takes aim at a similar service launched in March by Internet retail powerhouse Amazon.com, and is a long-coming step toward taking on Apple\'s iTunes digital content shop. \"This is something Google needed to do if the Android platform is to be taken seriously,\" said Gartner Research analyst Michael Gartenberg. \"Music is now table stakes,\" he continued. \"Google hasn\'t really raised the bar here, but you have to start somewhere.\" While Google Music isn\'t poised to be a major threat to iTunes, it should act as a lure that adds to Android\'s brisk momentum, according to the analyst. More than 200 million Android mobile gadgets have been activated worldwide, according to Google. Google early this year added movie rentals to its Android Market offering electronic books and other digital content for devices powered by Android.