[ServiceContract]
    public interface IServiceSendSMTP
    {

        [OperationContract]
        string GetData(int value);

        [OperationContract]
        CompositeType GetDataUsingDataContract(CompositeType composite);

        // TODO: Add your service operations here
        [OperationContract]
        bool SendMail(string Mail, string Subject, string Body);
    }


    // Use a data contract as illustrated in the sample below to add composite types to service operations.
    [DataContract]
    public class CompositeType
    {
        bool boolValue = true;
        string stringValue = "Hello ";

        [DataMember]
        public bool BoolValue
        {
            get { return boolValue; }
            set { boolValue = value; }
        }

        [DataMember]
        public string StringValue
        {
            get { return stringValue; }
            set { stringValue = value; }
        }
    }

public class ServiceSendSMTP : IServiceSendSMTP
    {
        public string GetData(int value)
        {
            return string.Format("You entered: {0}", value);
        }
        
        public CompositeType GetDataUsingDataContract(CompositeType composite)
        {
            if (composite.BoolValue)
            {
                composite.StringValue += "Suffix";
            }
            return composite;
        }

        #region IService1 Members


        public bool SendMail(string Mail, string Subject, string Body)
        {
            SmtpClient Smtp = new SmtpClient("smtp.mail.ru",25);
            System.Net.NetworkCredential SmtpUser = new System.Net.NetworkCredential("cam","****");
            Smtp.Credentials = SmtpUser;
            Smtp.UseDefaultCredentials = false;
            MailMessage message = new MailMessage("ca@mail.ru", Mail, Subject, Body);
            Smtp.Send(message);
            return true;
        }

            ServiceReferenceMail.ServiceSendSMTPClient send = new smtp.ServiceReferenceMail.ServiceSendSMTPClient();
            bool sends = send.SendMail("boris@gmail.com", "test", "tesssrt");
            MessageBox.Show(sends.ToString());