Just about finished a beta, although I haven't implemented emailing any errors back to me yet. From reading it seems that some ISPs attempt block port 25 and/or other ports as part of an anti spam campaign, however, this is unlikely to have any effect on most users which means using email is still a viable option in my case.

So what is the goodest way for me, once the users click yes they assent to sending me the errors, to automate the error mail back to my online email account (Fastmail)?

Note: they are not necessarily going to be logged in with admin rights (not elevated) and they might be behind a firewall.

My email server info is:
SMTP - Regular
Note: "Guest" accounts do NOT have SMTP access. Use ISP's SMTP server instead or upgrade
Server: mail.messagingengine.com
Port: 587 (preferred) or 25 or 26 including STARTTLS support (or SSL SMTP port 465)
Authentication: PLAIN (Our SMTP ports are for authenticated SMTP only; you'll need to make sure your software supports authenticated SMTP and also set up a username and password)
Username: your FastMail.FM username/login name/email address (must include @fastmail.fm part)
Password: your FastMail.FM password

Firewall access
FastMail.FM has a special proxy system whereby you can access each service (POP, IMAP, SMTP, etc) through any port number. The server names are:
SMTP: smtp-proxy.messagingengine.com
SMTP/SSL: smtps-proxy.messagingengine.com