Spotify, the free ad-supported music streaming service has finally released its music waves to the US market rivaling the likes of Pandora and Rhapsody.

The American service had been put on hold after American record labels voiced concerns that the service would not generate enough money. As a result the American version will have more restrictions but it is basically the same as the popular European version.

Users can listen free to any track, on demand, without having to choose a radio station like Pandora, however, audio ads will be streamed  every few tracks unless you upgrade to the Premium service priced at $5 per month. The Unlimited $10 monthly package allows offline storage of tracks and the ability to use the service on a mobile device.

In addition to its extensive music catalogue Spotify will allow you to scan your iTunes library and play the tracks on your Spotify app.

We believe that music is the most social thing there is and that's why we've built the best social features into Spotify for easy sharing and the ultimate in music discovery, said Spotify CEO Daniel EK

How to sign up:

Like Google + the service has been launched in an invite-only phase. Sign up for an invitation to the  free version here by submitting your email address. For those who can't wait you can sign up directly for Spotify Premium starting at $4.99 monthly. Klout, the online influence measurer, is also giving out Spotify invites. See if you are eligible.