Mandar mail con ASP.NET 2.0 (See related posts)

MailMessage message = new MailMessage();
message.From = new MailAddress("remitente@lo.que.sea");
message.To.Add(new MailAddress("destinatario@lo.que.sea"));
message.Subject = "Asunto";
message.Body = "Cuerpo";
SmtpClient client = new SmtpClient();
client.Send(message);

<system.net>
    <mailSettings>
        <smtp from="email@algo.com">
            <network host="localhost" port="25" defaultCredentials="true" />
        </smtp>
    </mailSettings>
</system.net>