I'm still trying to grok, as they say, MVVM in Silverlight.  So if any of
this sounds ignorant, don't be shy about letting me know.

So essentially I have a ViewModel such as this:

    public class MainLayoutViewModel : ViewModelBase
    {
        private LoginViewModel m_loginController = new LoginViewModel();
        private TestViewModel m_testController = new TestViewModel();
        private ViewModelBase m_currentViewModel;

        public MainLayoutViewModel()
        {
            CurrentViewModel = m_loginController;
        }

        public ViewModelBase CurrentViewModel
        {
            get { return m_currentViewModel; }
            set
            {
                m_currentViewModel = value;
                InvokePropertyChanged("CurrentViewModel");
            }
        }
    }

Now when my LoginViewModell "authenticates", I suppose I want to change the
"CurrentViewModel" property to a new view model.  In my View, I would like
to change the DataTemplate "View" to the matching ViewModel, but it seems
something like this is not supported in SL.  I found some great support for
this in the SL Extensions <http://slextensions.net> (ResourceSelector), *but
I was wondering how everyone else does this, or if there is a better way* or
if I'm just doin' it wrong?  My View with the SL extension looks like this:

<UserControl x:Class="SKMEventUI.MainLayoutView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:Views="clr-namespace:MyNamespace.Views"
    xmlns:Data="clr-namespace:SLExtensions.Data;assembly=SLExtensions"

xmlns:Controls="clr-namespace:SLExtensions.Controls;assembly=SLExtensions.C ontrols">
    <UserControl.Resources>
        <Data:ResourceSelector x:Key="controlTemplateSelector">
            <ResourceDictionary>
                <DataTemplate x:Key="LoginViewModel">
                    <Border BorderBrush="Black" BorderThickness="1,1,1,1">
                        <Views:LoginView/>
                    </Border>
                </DataTemplate>
                <DataTemplate x:Key="TestViewModel">
                    <Views:TestView />
                </DataTemplate>
            </ResourceDictionary>
        </Data:ResourceSelector>
        <DataTemplate x:Key="controlItemTemplate">
            <ContentControl Content="{Binding}"
                            ContentTemplate="{Binding
Converter={StaticResource controlTemplateSelector}}" />
        </DataTemplate>
    </UserControl.Resources>
    <StackPanel x:Name="LayoutRoot" Background="White">
                <ContentControl  Content="{Binding CurrentViewModel}"
                         ContentTemplate="{StaticResource
controlItemTemplate}" />
    </StackPanel>
</UserControl>