I'm just back from a weeks holiday, during which I used my 6110 Navigator to check my emails every now and again. Unfortunately I didn't quite have the settings sorted out completely to allow me to send email from my phone, so I had to wait until I got home to a proper internet connection again to investigate further and review what those settings should be. Anyway, for the record, those settings (found under Messaging -> Options: Settings -> Email -> Mailboxes -> [mailbox name] -> Connection Settings -> Outgoing e-mail) are:

My e-mail address, User name and password - normal settings
Outgoing mail server: smtp.googlemail.com
Security (ports): StartTLS
Port: 587

This seems to work :-)