Google today officially announced its new music subscription service, Google Play Music All Access, at the Google I/O conference in San Francisco. As reported yesterday afternoon, the service is designed to compete with Spotify, providing songs on demand that can be streamed to a computer or mobile device. The service, which is built on Google's existing Google Play Music Store, will cost $9.99 per month with a 30-day free trial available. Google is, however, offering a discount for early adopters. Those who begin the free trial by June 30 will pay just $7.99 per month.