Turntable.fm has confirmed that it has closed a $7 million funding round, details of which were initially revealed last month. The social music service has also launched its iPhone app in the App Store.

Union Square Ventures led the funding round and Fred Wilson, a partner at the VC firm, is joining the Turntable.fm board. Others who have participated in the round include First Round Capital, Polaris Venture Partners, Lowercase Capital and Benchmark Capital. Several angel investors participated in the round too, including Troy Carter (Lady Gaga‘s manager), Guy Oseary (Madonna‘s manager) and former Facebook director Tim Kendall.

Turntable.fm has more than 600,000 users, just 3 months after launching. Previously, you needed to have an invite from a Facebook friend who was already using Turntable.fm, but that requirement has now been dropped and anyone in the U.S. can now take part in the open beta of Turntable.fm. However, the company is working hard to launch in other countries and open up as soon as possible.

Meanwhile, the company has launched its iPhone app so that you can DJ on Turntable.fm from anywhere — we reported last week that the app was on the way. You can access all of the virtual rooms on Turntable.fm and rate songs as lame or awesome. The app lets you chat with others in a room and become a fan of your favorite DJs so you can find them easily. You can create your own rooms and DJ within existing rooms using the app too.

If you’d like to check out the Turntable.fm app, you can download it on your iPhone now. There is no word on the app being released on other platforms at this time.