It appears that to enable email on my i-mate SP3 I needed to enable WAP. Enabling an internet connection was not enough. To setup WAP I needed to create a dialup account using the WAP Network option and the *99# number. No user name, password or domain entries were required.
The actual network setting is set to Internet. Setting the network directly to WAP does not seem to work but with a WAP entry being setup, even though it is not directly accessed seems to do the trick.
Virgin Mobile do not, as far as I know, have their own publically usable email servers so you need to specify both incoming (POP3) and outgoing (SMTP) servers as your own email servers (Personally I use vbCity's email server)