I’ve mentioned a number of excellent iOS controls for creating customized popups such as OGActionChooser and most recently this control for creating a modal popup with nav bar.
This library allows you to display a ViewController as a popup so you can put whatever content you like within.
The library provides a number of entrance and exit animations for the popups, and the popups can vanish when the background is touched or when a close method is run.
Here’s a video showing this custom control in action:
You can find the library from Martin on Github here.
Another controller providing a nice alternative to a UIActionSheet or UIAlertView.