Starting Internet Explorer from a Windows Phone (WP7) Application

Starting Internet Explorer from a Windows Phone (WP7) Application 

using Microsoft.Phone.Tasks; namespace WindowsPhoneLaunchExternal
{
    public partial class MainPage : PhoneApplicationPage
    {
        private void hyperlinkbuttonExternal_Click(object sender, RoutedEventArgs e)
        {
            WebBrowserTask task = new WebBrowserTask();
            task.URL = textboxUrl.Text;
            task.Show();
        }
    }
}