Awesome
FloatLabeledEntry
This library provides a UI component for Xamarin.iOS apps that creates a floating placeholder effect. There are two versions available:
FloatLabeledEntry
Includes a FloatLabeledTextField
class, based on a standard iOS text field
FloatLabeledEntry.Dialog
Includes a FloatLabeledEntryElement
class, for MonoTouch.Dialog applications
This library started as a port of Jared Verdi's JVFloatLabeledTextField and Matt D. Smith's original design: