Sparrow has been available on OS X for some time now, gaining a cult-like following, with its loyal users clamoring for an iOS app to complement their Mac experience. Their wishes have seemingly been granted. With its panel navigation, its new threading system and many new features, Sparrow promises that “you’ll never look back” when it comes to viewing and sending emails on the go. Key features include one-touch swipe capabilities, up and down conversations, and a twp-step composer. Sparrow for iPhone is now available in the App Store for $3 USD.