Hola amigos..
Este es el codigo probado por si alguien lo necesita:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication3
{
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
richTextBox1.Text += ((char)13).ToString() + ((char)13).ToString() + richTextBox2.Text;
}
private void Form2_Load(object sender, EventArgs e)
{
DateTime dt = DateTime.Now;
richTextBox2.Text = dt.ToLongDateString() + ((char)13).ToString();
richTextBox2.Select(richTextBox2.Text.Length, 0);
}
}
}