Silverlight 2 has a Timer (DispatcherTimer)

public partial class Timer : UserControl
 {
 public delegate void TimerFiredHandler();
 
 public event TimerFiredHandler TimerFired;
 
 public Timer()
     {
         InitializeComponent();
         TimeUnit.Completed += new EventHandler(TimeUnit_Completed);
     }
 
 void TimeUnit_Completed(object sender, EventArgs e)
     {
         TimeUnit.Begin();
 if (TimerFired != null)
             TimerFired();
     }
 
 public void StartTimer()
     {
         TimeUnit.Begin();
     }
 }

Timer t = new Timer();
 
 Container.Children.Add(t);
 
 t.TimerFired += new Timer.TimerFiredHandler(t_TimerFired);
 
 t.StartTimer();
 
 
 void t_TimerFired()
 {
 // Do Stuff here.
 }

System.Windows.Threading.DispatcherTimer dt = new System.Windows.Threading.DispatcherTimer();
 dt.Interval = new TimeSpan(0, 0, 0, 0, 500); // 500 Milliseconds
 dt.Tick += new EventHandler(dt_Tick);
 dt.Start();
 
 void dt_Tick(object sender, EventArgs e)
 {
 // Do Stuff here.
 }