function goto(url) {
   window.open(url);
}

HtmlPage.Window.Invoke("goto", "http://broux.developpez.com");

HtmlPage.Window.Navigate(new Uri("http://broux.developpez.com", UriKind.Absolute), "_blank");

System.Windows.Browser.HtmlPage.Document.QueryString["NomDuParametre"] = Valeur;

HtmlDocument doc = HtmlPage.Document;
doc.GetElementById("IDduControl");

HtmlPage.Document.DocumentUri.OriginalString;

System.Windows.Browser.HtmlPage.Window.Navigate(new Uri("url", UriKind.Absolute));

function CloseWindow()
{
    window.close();
}

HtmlPage.Window.Invoke("CloseWindow");

<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<div style="height:100px">
    <asp:Silverlight ID="Xaml1" runat="server" Source="~/ClientBin/monApplication.xap" MinimumVersion="2.0.30523" Width="100%" Height="100%" />
</div>
<div id="result"></div>

private void Button_Click(object sender, RoutedEventArgs e)
{
    var element = HtmlPage.Document.GetElementById("result");
    element.SetAttribute("innerText", "valeur venant de Silverlight");
}