OxyPlot is what I mess around with some as well. If I remember correctly, it has a Xamarin.Android version as well (available on their main page), although it is in Alpha.
Hi now I'm currently working in task called annotation. I go through the annotation sample of monotouch https://github.com/Emasoft/OxyPlot.2DGraphLib.MonoTouch. Its working fine but I need the annotat