Configuring mutt to send e-mail over an SSH tunnel

Using remote SMTP is described here: http://wiki.mutt.org/?MuttFaq/Sendmail
So with the tunnel you'd set up your SMTP to localhost, but with the tunnel port. Eg. you create tunnel 8025->25 on remote:

ssh -L8025:smtp.example.com:25 serv.example.com

And in Mutt configuration (.muttrc) you put:

set smtp_url="smtp://username@localhost:8025/"

BTW. Using remote POP/IMAP here: http://wiki.mutt.org/?MuttFaq/RemoteFolder