Couple of errors that im unsure on (c#)

using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Mail;



namespace Email
{
    class Program
    {
        static void Main(string[] args)
        {
            string to;
            string subject;
            string message;
            string from;
            int times;
            MailMessage mail;

            Console.WriteLine("To, Subject, Message, from");
            to = Console.ReadLine();
            subject = Console.ReadLine();
            message = Console.ReadLine();
            from = Console.ReadLine();

            mail.To = to;
            mail.Subject = subject;
            mail.Body = message;

            SmtpClient smtp;

            smtp.Host = "localhost";
            smtp.Send(mail);


            Console.ReadLine();
            


        }
    }
}

Error    1    Property or indexer 'System.Net.Mail.MailMessage.To' cannot be assigned to -- it is read only    D:\Documents and Settings\Jason\My Documents\Visual Studio 2005\Projects\Email\Email\Program.cs    27    13    Email


Error    2    Cannot implicitly convert type 'string' to 'System.Net.Mail.MailAddressCollection'    D:\Documents and Settings\Jason\My Documents\Visual Studio 2005\Projects\Email\Email\Program.cs    27    23    Email

mail.To.Add(to);

MailMessage mail = new MailMessage();

mail.From = new MailAddress(from);

mail.From = new MailAddress("[email protected]", "John Smith");