This example project demonstrates how to create a CalloutView similar
to the UICalloutView that's used in the iPhone Map application.

This is done without using any undocumented calls, the CalloutView is
constructed using a regulare UIView subclass and consists of a set
of three UIImageViews, a UILabel, and a UIButton.

Although this example is written in MonoTouch, it's not using any
Mono-specific classes, so converting it to Objective-C should be
straightforward.