NuOxygen Game Publishing has released Umotion 2D (http://macte.ch/ZFHth), a new 2D animation tool for Macintosh and Windows systems. A demo version is available.
Using this tool you can create 2D animations and export them directly into Unity, Umotion 2D comes with tutorial videos and a short user guide.
You only need to work with the separate elements from your texture Atlas and not the whole animation sequence. Furthermore, you can use Umotion to resize complex 2D games with bigger 2D animations with Unity for iPhone and iPad. The final result is similar to what you get when creating animations with a 3D software like Maya or 3DMax, only you are working into a 2D environment.
