TestFlight simplifies iPhone app testing with over-the-air distribution
With TestFlight, you can say goodbye to emailing out updated .ipa files and asking testers to manually sync them via iTunes. Instead, you get over-the-air distribution to your whole list of testers -- grouped, if you want, so you can test multiple versions of your app at the same time! -- and an easy-as-pie version manager. No wonder the makers of apps like Tweetie, The Incident, and Posterous all gave gushing testimonials for the TestFlight website.
If you want to demo TestFlight, you can (no joke) drag your .ipa to a box on testflghtapp.com, enter some email addresses, and hit submit. Then, just watch the counter tick up as your testers install the app. That's why they call it "magical." TestFlight is free for developers, and enterprise accounts are available if you email the devs.