you need smtp relay or gateway. I use http://sendgrid.com/ to send emails from the cloud, they have a free option.
there is also sample code on how to send emails, I re-factored their code so I could call it from other places.
public partial class Email
{
/// <summary>
/// Generic Email method used to send email through SendGrid
/// </summary>
/// <param name="ToAddressName">ToAddress, DisplayName</param>
/// <param name="FromAddress">Email address of sender</param>
/// <param name="FromName">Display Name of sender</param>
/// <param name="SendCopy">Send BCC to FromAddress</param>
public void SendEmail(Dictionary<string, string> toAddressName,
                      String fromAddress, String fromName,
                      String subject, String message,
                      bool sendCopy)
{
  try
  {
    MailMessage mailMsg = new MailMessage();
    // To
    foreach (KeyValuePair<string, string> kvp in toAddressName)
    {
      string toAddress = kvp.Key;
      string displayName = kvp.Value;
      mailMsg.To.Add(new MailAddress(toAddress, displayName));
    }
    // From
    mailMsg.From = new MailAddress(fromAddress, fromName);
    if (sendCopy)
    {
      mailMsg.Bcc.Add(new MailAddress(fromAddress, fromName));
    }
    // Subject and multipart/alternative Body
    mailMsg.Subject = subject;
    string html = message;
    mailMsg.AlternateViews.Add(AlternateView.CreateAlternateViewFromString(html, null, MediaTypeNames.Text.Html));
    // Init SmtpClient and send
    SmtpClient smtpClient = new SmtpClient("smtp.sendgrid.net", Convert.ToInt32(587));
    System.Net.NetworkCredential credentials = new System.Net.NetworkCredential("sendgridusername", "sendgridpassword");
    smtpClient.Credentials = credentials;
    smtpClient.Send(mailMsg);
  }
  catch (Exception ex)
  {
    Error error = new Error();
    error.ReportError(ex);
  }
}
(ps if you have any comments on my code I would love to hear it, thanks)