System.Web.Mail.MailMessage message=new System.Web.Mail.MailMessage();

message.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/smtpauthenticate",1 );
message.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/sendusername","SmtpHostUserName" );
message.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/sendpassword","SmtpHostPassword" );

message.From="from e-mail";
message.To="to e-mail";
message.Subject="Message Subject";
message.Body="Message Body";

System.Web.Mail.SmtpMail.SmtpServer="SMTP Server Address";
System.Web.Mail.SmtpMail.Send(message);