A simple helper class for monotouch which provides you an easy to use API for showing alerts with buttons. The class will handle the reference tracking and alert queue for you.

UIAlertHelper.cs

namespace Fusonic.Monotouch.Utils
{
	public class ButtonAction
	{
		public ButtonAction (string title, Action callback)
		{
			Title = title;
			Callback = callback;
		}
		
		public string Title { get; set; }
		public Action Callback { get; set;}
	}
	
	public class UIAlertHelper
	{			
		private static readonly List<UIAlertView> activeViews = new List<UIAlertView>();
		private static readonly List<UIAlertView> queuedViews = new List<UIAlertView>();
		
		public static void ShowAlert(string title, string message, string cancelButtonTitle, params ButtonAction[] actions)
		{
			string[] buttons = (actions != null) ? 
				actions.Select(x => x.Title).ToArray() : null;
						
			
			UIAlertView alertView = new UIAlertView(title, message, null, cancelButtonTitle, buttons);
			alertView.Clicked += (sender, e) => HandleAlertViewClicked(alertView, e, actions);
			alertView.Dismissed += HandleAlertViewDismissed;			
			
			if(activeViews.Count == 0)
			{
				alertView.Show();
				activeViews.Add(alertView);
			}
			else
			{
				queuedViews.Add(alertView);
			}
		}

		static void HandleAlertViewDismissed (object sender, UIButtonEventArgs e)
		{
			UIAlertView alertView = (UIAlertView)sender;
			
			if(activeViews.Contains(alertView))
			{
				activeViews.Remove(alertView);
				
				if(queuedViews.Count > 0)
				{
					UIAlertView first = queuedViews.First();
					first.Show();
					activeViews.Add(first);
					queuedViews.Remove(first);
				}
			}
		}
		
		static void HandleAlertViewClicked (UIAlertView alertView, UIButtonEventArgs e, ButtonAction[] actions)
		{
			if(actions == null) {
				return;
			}
			
			string title = alertView.ButtonTitle(e.ButtonIndex);
			
			ButtonAction action = actions.SingleOrDefault(x => x.Title == title);
			if(action != null)
			{
				action.Callback();
			}
		}
	}
}