We haven’t heard much about Google Music, the company’s cloud-based music locker service, since it launched back in May at the I/O developer conference. Getting in to try it was tough – you had to be US-only to apply to join for a start, and the timing of when your account was approved was entirely up to Google, as it looked to control the number of people using the fledgling service.

Now Google Music is starting to open up a little. Existing users have been granted two invites each, to hand out as they choose. It’s still US only though, so anyone outside the fifty states will have to continue holding on.

Google Music, which lacks any music industry licensing deals at present, requires you to upload all your music but then lets you listen to it, streaming from the cloud via a Web app and Android app. It’s something of a poor relation to Amazon’s Cloud Player and Cloud Drive, which throws in integration with Amazon’s MP3 Store (no need to upload anything you buy there) and Apple’s forthcoming iTunes Match service which will give you a cloud-based music library based on songs on your computer without any uploads required.

All three services, are US only for the time being, thanks – as ever – to those ever-present licensing issues.

Screen Shot 2011 07 29 at 13.19.16 Google starts to open up its cloud music service with user invites, still US only