iPad 2 : Email on wifi ?

[PostmanPot]

AFAIK your ISP should have different SMTP settings that will allow you to send emails via other ISPs.

[undesign]

The solution usually is to use authenticated outbound sending (if supported), which should forego the source IP checking.

That. You can now blissfully mail away on different ISPs or 3G without having to worry about which SMTP server to use.