There were no shortage of details regarding Apple’s much rumored radio service leading up to today’s keynote address. The rumors said Apple was planning on introducing a free, ad-supported radio service, similar to Pandora, that would be highly integrated with a tweaked model for its iAd business. Apple has now officially unveiled the service dubbed ‘iTunes Radio’ and provided some details on exactly how it will work during its keynote presentation this morning at Moscone West in San Francisco.

The new iTunes Radio app is built in to the iOS radio app, and works on the Mac and Apple TV as well. As rumored, iTunes Radio will be free, supported by ads. In a twist, however, iTunes Radio will be completely free (free of ads) if you’re a subscriber to iTunes Match:

As we reported prior to today’s event, the underlining technology is based on Apple’s iTunes Genius feature with iTunes Radio tailoring the experience to your iTunes usage. Apple says there will be Siri integration, and also aims to offer users “access to exclusive “first listen” premieres from top selling artists.”

Earlier this month reports from The Wall Street Journal, Bloomberg, and others said that Apple would be introducing its radio service based on an altered iAd model that would include both audio ads and traditional app-like iAds. Apple has reportedly signed up Sony, alongside the other major labels, Warner and Universal, to include their catalogs of music in the new radio service.

One thing that wasn’t clear ahead of today’s event what type of functionality Apple’s radio service would provide compared to Pandora and other competitors. We knew that the technology was based largely on Apple’s iTunes Genius already available on iOS and Mac, but it wasn’t clear what type of control users would have over the experience. From Apple’s brief demo, it appears that the service will center largely on curated playlists, including integration with Twitter for trending music, and will allow users to skip to the next song in a playlist. It will also allow users to search for specific artists.

The service will roll out initially in the US only with iOS 7 this Fall.