This is a MonoTouch Binding for Matej Bukovinski's MBProgressHUD Objective-C library
see more on https://github.com/jdg/MBProgressHUD
Just add AlexTouch.MBProgressHUD.dll to your project references in MonoDevelop.
You can create your hud using c# like this
var hud = new MBProgressHUD(this.View);
hud.Mode = MBProgressHUDMode.Determinate;
hud.LabelText = "Loading...";
hud.DetailsLabelText = "Some Description here";
this.View.AddSubview(hud);
hud.Show(true);
Also you can know when the hud was hidden using the following event
hud.WasHidden += delegate
{
Console.WriteLine("Hud hidden");
};