I wanted to have a cfmail tag use my Gmail SMTP to send mail, which was relatively straightforward, but there is some vague language in the Google help doc that didn't immediately translate to cfmail attribute settings. I did find plenty of search results on the topic, but most threads were a little confusing and noted differing experiences between developers. So I've taken a little time to experiment and thought I'd share the results.
From both my gmail.com account and my Google Apps for Your Domain mail (gmail for custom domain name) accounts I was able to find the same help doc for standard POP/SMTP configuration.
We can quickly deduce that the username attribute should be your full e-mail address (including @gmail.com or @your_domain.com), and the password is of course your Gmail password.
The help doc provides the following information for the outgoing/SMTP server configuration:
smtp.gmail.com (use authentication)
Use Authentication: Yes
Use STARTTLS: Yes (some clients call this SSL)
Port: 465 or 587
So, how does the above information translate to relevant cfmail tag attributes (server, port, username, password, useSSL, useTLS)? It's a bit more specific than the Gmail help doc suggests...