Send mail with .net 2.0

first of all you must use System.Net.Mail :
using System.Net.Mail;

Then it's a easy task :
MailMessage message = new MailMessage();
message.From = new MailAddress("sender@microsoft.com");
message.To.Add(new MailAddress("recipient@foo.bar.com"));
message.CC.Add(new MailAddress("cc@foo.bar.com"));
message.Subject = "This is my subject";
message.Body = "This is the content";

SmtpClient client = new SmtpClient();
client.Send(message);

to confgure the smtp client there is 2 ways:
1- using client instance : client .Host = "MailServer";
2- add the folowing directive to the web.config for ASP.net/app.config for winform:
network host="MailServer" port="25" userName="username" password="secret" defaultCredentials="true"