SoundCloud has launched SoundCloud Labs, a site dedicated to experimental projects and features built on its API. The company also announced a partnership that enables a SoundCloud-supported mp3 streams directly in the Facebook feeds of Headliner.fm artist marketing campaigns

With Labs, SoundCloud users can access prototypes and apps that extend the platform. “While creating new opportunities for our users, we’re also able to showcase the potential of our API and continue to encourage third-party developers to build their own apps on our platform”

Starting today, four features are available in Labs

• Social Unlock - create a customised page to promote and stream music then reward fans with a download when they share the track link via Twitter
• Importer -  More options to get your sounds onto your SoundCloud account including the ability  to import tracks from a URL, via email or phone.
• Google Apps Gmail Plugin – SoundCloud waveform players are automatically included for track and set links in received emails, allowing anyone to play your sound from within the message (currently for Google Apps accounts only)
• Takes Questions - A simple, personalized audio Q&A.

SoundCloud users can also access more than 150 apps created  by third-party developers with the newest launched just yesterday by Headliner FM. Now, when a Headliner.fm user creates a promotion, they can include a SoundCloud-supported Mp3 stream that will place their music directly in the Facebook feed of potential fans.

Headliner.fm offers musicians the ability to reach new fans who like similar music by having other artists recommend them to their fans on Facebook, Twitter, and MySpace.  In the last month, 16,000 artists reaching 40 million new fans joined the network, according to the company.