Radioplayer launched at the end of March with 157 stations from the BBC and commercial radio. There are now more than 250 stations available, many of which have fan and group pages on Facebook already.
Facebook Radioplayer app users can receive recommendations based on their friends listening habits as well as geographical recommendations based on where they live.
Information about the station the user is listening to will be posted to their wall and later versions of the player will also offer recommendations based on users' profiles, such as music tastes and age.
The app appears exactly the same as the Radioplayers used by individual stations as pop-ups on their websites. Any advertising booked with the commercial stations will be visible on the player within Facebook.
It was created as a research project through Facebook Connect developer tools but testing in the past three to four weeks proved so successful that Radioplayer decided to launch the service.
Folder Media, working with Radioplayer, was the app's lead developer, with UBC Media's Unique Interactive providing the technical support and Media UK providing the station data feeds.
Michael Hill, managing director of Radioplayer, said: "Less than six months ago we put 'UK Radio in one place' on your computer. Now we're showing 30 million UK Facebook users that radio is a perfect companion, while you're chatting with friends."
In the most recent figures available, Radioplayer revealed at the start of June that it achieved 5.7 million unique users over a four-week period, generating a total of 22.5 million listening sessions.
In addition to being a content partner of internet connected TV consortium YouView (set to launch in 2012) Radioplayer is looking to launch on other platforms such as mobile phones and tablets.
Radioplayer is an open platform all Ofcom licensed radio stations can join and it currently offers all BBC national and local stations as well as commercial radio, independent, student and community stations.
Andrew Harrison, chairman of Radioplayer and chief executive of commercial radio trade body RadioCentre, said: "These latest developments are part of a long-term strategy which will see Radioplayer form a vital component of the radio industry’s multiplatform future alongside DAB and FM."