<service behaviorConfiguration=
    "MySilverlightWcfService.NWServiceGatewayBehavior"
    name="MySilverlightWcfService.NWServiceGateway">
    <endpoint address="" 
        binding="basicHttpBinding"
        contract="MySilverlightWcfService.INWServiceGateway" />
    <endpoint address="mex" binding="mexHttpBinding" 
        contract="IMetadataExchange" />
</service>

[ServiceContract(Namespace = "")]
public interface INWServiceGateway
{
    [OperationContract]
    Product FindProduct(int productId);
    [OperationContract]
    List<Product> FindProductList();
    [OperationContract(Name="FindProductListByCategory")]
    List<Product> FindProductList(int categoryID);
    [OperationContract]
    List<Category> FindCategoryList();
    [OperationContract]
    void SaveProduct(Product product);
}

<?xml version="1.0" encoding="utf-8"?>
<access-policy>
  <cross-domain-access>
    <policy>
      <allow-from http-request-headers="*">
        <domain uri="*"/>
      </allow-from>
      <grant-to>
        <resource path="/" include-subpaths="true"/>
      </grant-to>
    </policy>
  </cross-domain-access>
</access-policy>

<?xml version="1.0" encoding="utf-8"?>
<access-policy>
  <cross-domain-access>
    <policy>
      <allow-from http-request-headers="*">
        <domain uri="http://johnpapa.net"/>
      </allow-from>
      <grant-to>
        <resource path="/MyAwesomeServices/" include-subpaths="true"/>
      </grant-to>
    </policy>
  </cross-domain-access>
</access-policy>

<ListBox x:Name="lbProducts" Height="220" HorizontalAlignment="Left"
    VerticalAlignment="Bottom" Margin="10,10,10,10" Width="480" 
    Style="{StaticResource ListBoxStyle}" 
    ItemsSource="{Binding}" >

lbProducts.DataContext = productList;

Text="{Binding ProductName, Mode=OneWay}"

private void FindProductList()
{
    this.Cursor = Cursors.Wait;
    var proxy = new NWServiceGatewayClient();
    proxy.FindProductListCompleted += new 
        EventHandler<FindProductListCompletedEventArgs>(
        FindProductListCompleted);
    proxy.FindProductListAsync();
}

private void FindProductListCompleted(object sender, 
    FindProductListCompletedEventArgs e)
{
    ObservableCollection<Product> productList = e.Result;
    lbProducts.DataContext = productList;
    if (lbProducts.Items.Count > 0)
        lbProducts.SelectedIndex = 0;
    this.Cursor = Cursors.Arrow;
}

<TextBox Style="{StaticResource TextBoxStyle}"
    Text="{Binding UnitsInStock, Mode=TwoWay}" 
    Grid.Row="1" Grid.Column="1" Margin="3,3,3,3" Height="30" 
    x:Name="tbUnitsInStock" Width="100" 
    VerticalAlignment="Bottom" HorizontalAlignment="Left"/>

<TextBlock Style="{StaticResource TextBlockStyle}" Text="{Binding 
    CategoryName, Mode=OneWay}" Foreground="#FF001070" Grid.Row="1"
    Grid.Column="4" Margin="3,3,3,3" Height="22" 
    HorizontalAlignment="Left" VerticalAlignment="Bottom"/>

public override event PropertyChangedEventHandler PropertyChanged;

[DataContract]
public abstract class EntityBase : INotifyPropertyChanged    
{
    protected void PropertyChangedHandler(EntityBase sender, 
        string propertyName)
    {
        if (PropertyChanged != null)
            PropertyChanged(sender, new PropertyChangedEventArgs(
                propertyName));
    }
    public virtual event PropertyChangedEventHandler PropertyChanged;  
}

[DataMember]
public decimal UnitPrice
{
    get { return _unitPrice; }
    set
    {
        _unitPrice = value;
        base.PropertyChangedHandler(this, "UnitPrice");
    }
}