Spotify has removed the invite-only requirement for US members looking to try the popular streaming music service and introduced a free six month trial for all new users. The news comes a day after Spotify CEO Daniel Ek took the stage at Facebook's f8 developer conference to announce that his company would be one of more than a dozen joining the social network's new Open Graph platform.

The free trial lasts for six months, which is more than enough time to decide if you want to pay for the service moving forward. Free users are required to sign into the service using their Facebook account, which will then post updates from Spotify on friends' ticker. A quick check in the preferences reveals that you can disable publishing playlists and sending music you play to Facebook's Open Graph.

There are a few perks to look forward as a Spotify Premium user. Members of the $9.99 per month service enjoy unlimited music without advertising to their computer and mobile phone. Furthermore you can sync your favorite playlists, making them available offline whenever you want to listen. Premium streams are offered at a bit rate of up to 320kbps when using your computer. An add-free version of Spotify without all of the aforementioned perks can be yours for $4.99 if you don't want to shell out $5 more for mobile phone support and offline content.

The free six month trial opens up nearly every feature of Spotify. In the limited time I have used the service today, I haven't experienced any ads and the app works perfectly on my mobile phone as well as my PC. I did receive an email welcoming me to a "48 hour free premium trial", although it's very possible that the company simply hasn't updated their canned email response yet. I guess I'll find out for sure in two days.

Lifehacker backs my findings and further reports that once the free trial is over, users can either upgrade to a premium membership or continue listening free, although ads will be introduced and music listening will be capped at 10 hours per month, including what you listen to on Facebook.