Having issues with outgoing Godaddy mail as well.
Since I upgraded to iOs 4.3, I am unable to use smtpout.secureserver.net (GoDaddy's server) to send email if I'm not connected to WIFI. Once I'm connected to a WIFI station, it works fine. I haven't found a solution yet to use GoDaddy's SMTP on 3G yet.
For the record, the ports you can use are 25, 80, 587 and 3535. For SSL, you have to use port 465.