You'll also want to add the following code to your project to get the system date:

public partial class DboDataContext
{

    [Function(Name = "GetDate", IsComposable = true)]
    public DateTime GetSystemDate()
    {
        MethodInfo mi = MethodBase.GetCurrentMethod() as MethodInfo;
        return (DateTime)this.ExecuteMethodCall(this, mi, new object[] { }).ReturnValue;
    }
}

private static Dictionary<type,> _cachedIL = new Dictionary<type,>();

public static T CloneObjectWithIL<t>(T myObject)
{
    Delegate myExec = null;
    if (!_cachedIL.TryGetValue(typeof(T), out myExec))
    {
        // Create ILGenerator
        DynamicMethod dymMethod = new DynamicMethod("DoClone", 
                                      typeof(T), new Type[] { typeof(T) }, true);
        ConstructorInfo cInfo = myObject.GetType().GetConstructor(new Type[] { });

        ILGenerator generator = dymMethod.GetILGenerator();

        LocalBuilder lbf = generator.DeclareLocal(typeof(T));
        //lbf.SetLocalSymInfo("_temp");

        generator.Emit(OpCodes.Newobj, cInfo);
        generator.Emit(OpCodes.Stloc_0);
        foreach (FieldInfo field in myObject.GetType().GetFields(
           System.Reflection.BindingFlags.Instance | 
           System.Reflection.BindingFlags.Public | 
           System.Reflection.BindingFlags.NonPublic))
        {
            // Load the new object on the eval stack... (currently 1 item on eval stack)
            generator.Emit(OpCodes.Ldloc_0);
            // Load initial object (parameter)      (currently 2 items on eval stack)
            generator.Emit(OpCodes.Ldarg_0);
            // Replace value by field value         (still currently 2 items on eval stack)
            generator.Emit(OpCodes.Ldfld, field);
            // Store the value of the top on the eval stack into
            // the object underneath that value on the value stack.
            //  (0 items on eval stack)
            generator.Emit(OpCodes.Stfld, field);
        }

        // Load new constructed obj on eval stack -> 1 item on stack
        generator.Emit(OpCodes.Ldloc_0);
        // Return constructed object.   --> 0 items on stack
        generator.Emit(OpCodes.Ret);

        myExec = dymMethod.CreateDelegate(typeof(Func<t,>));
        _cachedIL.Add(typeof(T), myExec);
    }
    return ((Func<t,>)myExec)(myObject);
}

I got both of the above methods off of the net somewhere (maybe even from CodeProject), but it's been long enough that I can't recall where I got them.

Explanation of the History Class

The History class records changes by creating a TableHistory record, inserting the values for the primary key for the table being modified into the Key1, Key2, ..., Key6 columns (if you have more than 6 values that make up a primary key on any table, you'll want to modify this), setting the type of change being made in the ActionType column (INSERT, UPDATE, or DELETE), old value and new value if it happens to be an update action, and the date and Windows identity of the user who made the change.

Let's examine what happens when a call is made to the RecordLinqInsert method:

public static void RecordLinqInsert(DboDataContext dbo, IIdentity user, object obj)
{
    TableHistory hist = NewHistoryRecord(obj);

    hist.ActionType = "INSERT";
    hist.ActionUserName = user.Name;
    hist.ActionDateTime = dbo.GetSystemDate();

    dbo.TableHistories.InsertOnSubmit(hist);
}

private static TableHistory NewHistoryRecord(object obj)
{
    TableHistory hist = new TableHistory();

    Type type = obj.GetType();
    PropertyInfo[] keys;
    if (historyRecordExceptions.ContainsKey(type))
    {
        keys = historyRecordExceptions[type].ToArray();
    }
    else
    {
        keys = type.GetProperties().Where(o => AttrIsPrimaryKey(o)).ToArray();
    }

    if (keys.Length > KeyMax)
        throw new HistoryException("object has more than " + KeyMax.ToString() + " keys.");
    for (int i = 1; i <= keys.Length; i++)
    {
        typeof(TableHistory)
            .GetProperty("Key" + i.ToString())
            .SetValue(hist, keys[i - 1].GetValue(obj, null).ToString(), null);
    }
    hist.TableName = type.Name;

    return hist;
}

protected static bool AttrIsPrimaryKey(PropertyInfo pi)
{
    var attrs =
        from attr in pi.GetCustomAttributes(typeof(ColumnAttribute), true)
        where ((ColumnAttribute)attr).IsPrimaryKey
        select attr;

    if (attrs != null && attrs.Count() > 0)
        return true;
    else
        return false;
}