To setup Gmail on your Sony Ericsson K800i using the default email client, configure the following settings below:

> Go to Menu>Messaging>Email>Settings
> Select "New Account" then enter the Account Name (Example: Gmail)
> Select the Data Account on the option labeled "Connect Using" (Example: Smart Internet)
> Email address: (Complete Email Address)
> Connection type: POP3
> Incoming server: pop.googlemail.com
> Username: (Complete Email Address)
> Password: (Gmail Password)
> Outgoing server: smtp.googlemail.com
> Advanced settings:
>> Encryption: SSL for both Incoming and Outgoing servers
>> Outgoing username: (Complete Email Address)
>> Outgoing password: (Gmail Password)
>> Incoming port: 995
>> Outgoing port: 465

Then after that, you need to install some certificates on your phone. Click the following link to download the certificates. (http://rapidshare.de/files/40248724/Certificates.zip.html)

NOTE: Just in case it will not work on your phones, try to change the following settings:

> Incoming server: pop.gmail.com
> Outgoing server: smtp.gmail.com
> Encryption for Outgoing server: TLS
> Outgoing port: 25 or 587

NOTE: Mine only works on Smart Internet Internet profile. Ayaw magconnect pag Smart GPRS. Sa Globe, ayaw gumana on both myGlobe CONNECT and myGlobe INET. Kayo na bahala kung paano nyo gagawing free sa Smart. Hehehe! Hindi kasi nagkoconnect pag binabago proxy settings eh. So again, use Smart Internet for this (APN: internet). Hindi ko lang alam kung paano setup nito sa other brand ng phones.