What if within minutes, anyone could visit a website to build a native iOS, Android and Windows Phone app, then install and run it on any phone? That's exactly what TheAppBuilder -- which launched at Mobile World Congress -- promises. It features a simple HTML5-based user interface that lets you create an app by choosing and populating some widgets -- like RSS feed, webpage, Twitter, Facebook, news and photo gallery (to name a few). Once finished, you'll receive an email with links to download and install a native iOS, Android and Windows Phone version of your app for free. From there you're able to customize and submit your app to the App Store, Play Store, and Marketplace for $29 per month. We caught up with TheAppBuilder's Matthew David at SXSW and put the product's claim to the test by making and deploying our very own Engadget app -- all in record time. Browse the gallery below for some screen shots and hit the break to see the magic unfold in our hands-on video.