I fielded a question this week that may help other Silverlight 4 developers working with Esri products.  The question was how to add records to a table that lives inside a geodatabase.  While there is probably more then one way to skin this cat, here is one way to do this if you've got the Silverlight Toolkit installed.In short, I used the Feature Service. If other people have a different implementation feel free to share.
<UserControl x:Class="StandaloneTableEditing.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:esri="http://schemas.esri.com/arcgis/client/2009"
    xmlns:df="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.DataForm.Toolkit"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">
   �??- note the SL toolkit package is used here �?� 
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid x:Name="MyForm">
            <Grid.RowDefinitions>
                <RowDefinition Height="40" ></RowDefinition>
                <RowDefinition></RowDefinition>
            </Grid.RowDefinitions>
            <TextBlock Text="Silverlight Standalone Table Editing" Margin="10" FontSize="14" >
            </TextBlock>
            <df:DataForm x:Name="myDataForm" AutoEdit="False" CommandButtonsVisibility="All" Grid.Row="1" Width="400" Height="300" Margin="10" HorizontalAlignment="Left" VerticalAlignment="Top" >
            </df:DataForm>
        </Grid>
    </Grid>
</UserControl>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using ESRI.ArcGIS.Client;
using System.ComponentModel;
//Check to aake sure the System.ComponentModel reference has been added
namespace StandaloneTableEditing
{
    public partial class MainPage : UserControl
    {
        public string Owner { get; set; }
        public int Value { get; set; }
        public string Approved { get; set; }
        public int Lastupdate { get; set; }
        public Inspection inspection { get; set; }
        public FeatureLayer featurelayer { get; set; }
        public MainPage()
        {
            InitializeComponent();
            InitializeFeatureService();
            InitializeInspection();
            myDataForm.CurrentItem = inspection;  // Set up data form with data using the set Inspection Class below
        }
        private void InitializeInspection()
        {
            //Set up default values
            inspection = new Inspection()
            {
                Owner = "David Hasselhoff ",
                Value = 100,
                Approved = "Bay Watch",
                Lastupdate = 1111,
                InspectionFeatureLayer = featurelayer
            };
        }
        public void InitializeFeatureService()
        {
            featurelayer = new FeatureLayer();
            featurelayer.Url = "http://serverbox/ArcGIS/rest/services/EditingTables/FeatureServer/1";
            featurelayer.AutoSave = false;
            featurelayer.Mode = FeatureLayer.QueryMode.OnDemand;
            featurelayer.Initialized += Table_IsInitialized;
            featurelayer.Initialize();
            featurelayer.EndSaveEdits += Insert_EndSaveEdits;
            featurelayer.SaveEditsFailed += Insert_SaveEditsFailed;
        }
        public void Table_IsInitialized(object sender, EventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("it's initialized...");
        }
        public void Insert_SaveEditsFailed(object sender, EventArgs e)
        {
            string mes = e.ToString();  // For debugging
            System.Diagnostics.Debug.WriteLine(mes);
        }
        public void Insert_EndSaveEdits(object sender, EventArgs e)
        {
            string mes = e.ToString(); // For debugging
            System.Diagnostics.Debug.WriteLine(mes);
        }
    }
    public class Inspection : IEditableObject
    {
        public string Owner { get; set; }
        public int Value { get; set; }
        public string Approved { get; set; }
        public int Lastupdate { get; set; }
        public Inspection TempInspection { get; set; }
        public FeatureLayer InspectionFeatureLayer;
        public void BeginEdit()
        {
            // Save current Values
            TempInspection = new Inspection()
            {
                Owner = this.Owner,
                Value = this.Value,
                Approved = this.Approved,
                Lastupdate = this.Lastupdate
            };
        }
        public void CancelEdit()
        {
            // Reset Values
            Owner = TempInspection.Owner;
            Value = TempInspection.Value;
            Approved = TempInspection.Approved;
            Lastupdate = TempInspection.Lastupdate;
        }
        public void EndEdit()
        {
            ESRI.ArcGIS.Client.Graphic graphicAttribute = new ESRI.ArcGIS.Client.Graphic();
            graphicAttribute.Attributes.Add("OWNER", this.Owner);
            graphicAttribute.Attributes.Add("VALUE", this.Value);
            graphicAttribute.Attributes.Add("APPROVED", this.Approved);
            graphicAttribute.Attributes.Add("LASTUPDATE", this.Lastupdate);
            InspectionFeatureLayer.Graphics.Add(graphicAttribute);
            InspectionFeatureLayer.SaveEdits();
        }
    }
}
Regards, Doug Carroll, ESRI Support Services SDK Team http://support.esri.com/