Gmail for Mobile is very easy to setup.
Below are the following settings required for Gmail.
1st step is to enable POP in settings of your gmail account- VERY IMPORTANT
incoming server= pop.gmail.com
outgoing server= smtp.gmail.com
Incoming port= 995
Outcoming port= 465
Encryption= TSL incoming and outgoing
email address= username incliding @gmail.com
With Sony Ericsson phones the security certificates need to be downloaded to phone via http:/ as the standard certs. dont grant access.
The only issue i have is that some SOny ericsson phones require a domain name after encryption and i am not sure of this entry, so Maybe if anyone can add that than this would complete the gmail on your mobile using the email client on your phone instead of the tiresome WAP function.
Good luck and enjoy