This repo contains a UIView category called ShrinkTo which will let you easily shrink any view to a point within another view, much like the iOS Mail app.
[Here's a demo video.] (http://www.youtube.com/watch?v=Xak3xqGKvqc)
Make sure to link against the QuartzCore framework in your build settings or you'll get linker errors when you try to compile.
Call shrinkToCenterOfView: or shrinkToPoint:inView: on any UIView instance. The latter method takes a point in the second parameter's view coordinate system that specifies where the shrinking view should shrink to.
Thanks to Mike Nachbaur for guides on Core Animation.