[HTC Monet] maw123:
here are the o2 settings (lifted from modaco.com - thanks to smallfoot)

Contract

1) Start>Settings>Data Connections>Menu>Edit Connections

Dialup connection:

Description: O2 CSD WAP

Connects to: The internet

Phone number: +447712927927

User name: o2web

Password: password

Domain: blank

Proxy connection:

Description: O2 WAP proxy

Connects from: The Internet

Connects to: Wap Network

Proxy(name:port): 193.113.200.195:8080

Type: HTTP

Username:

Password:

GPRS Connection:

Description: O2 Internet

Connects to: The Internet

Access point: mobile.o2.co.uk

Username: o2web

Password: password

Primary DNS: 0.0.0.0

Secondary DNS: 0.0.0.0

I.P address: blank

GPRS connection:

Description: O2 GPRS WAP

Connects to: The internet

Access point: wap.o2.co.uk

Username: o2wap

Password: password

Primary DNS: 0.0.0.0

Secondary DNS: 0.0.0.0

I.P address: blank

GPRS connection:

Description: O2 MMS

Connects to: Secure WAP network

Access point: wap.o2.co.uk

Username: o2wap

Password: password

Primary DNS: 0.0.0.0

Secondary DNS: 0.0.0.0

I.P address: blank

In the main data connections menu.

Internet connection: O2 Internet

Work connection : Automatic

WAP connection: O2 GPRS WAP

Secure wap connection: O2 MMS

Start>Messaging>Media Messages>Menu>Options>Account Setup>Media Messages

Menu- Edit connections - Menu- Add

Server: O2 MMS

Download Messsages: automatically

Outgoing message size: less than 100kb

Allowed message types: personal

Menu>Edit connections

Description: O2 MMS

MMSC Address: http://mmsc.mms.o2.co.uk:8002

Data Connection: Secure WAP network

Gateway: WAP 1.0 Gateway

I.P Address: 193.113.200.195

Port: 9201

In Internet explorer, Menu-Options-Connections

Untick 'automatically detect settings'

Make 'Select network: The Internet' or 'Select Network: WAP network'.

O2 PAYG

1) Start>Settings>Data Connections>Menu>Edit Connections

Dialup connection:

Description: O2 CSD WAP

Connects to: The internet

Phone number: +447712927927

User name: o2wap

Password: password

Domain: blank

Proxy connection:

Description: O2 WAP proxy

Connects from: The Internet

Connects to: Wap Network

Proxy(name:port): 193.113.200.195:8080

Type: HTTP

Username:

Password:

GPRS Connection:

Description: O2 GPRS Wap

Connects to: The Internet

Access point: payandgo.o2.co.uk

Username: payandgo

Password: password

Primary DNS: 0.0.0.0

Secondary DNS: 0.0.0.0

I.P address: blank

GPRS connection:

Description: O2 MMS

Connects to: Secure WAP network

Access point: payandgo.o2.co.uk

Username: payandgo

Password: password

Primary DNS: 0.0.0.0

Secondary DNS: 0.0.0.0

I.P address: blank

In the main data connections menu.

Internet connection: O2 CSD WAP

Work connection : Automatic

WAP connection: O2 GPRS WAP

Secure wap connection: O2 MMS

Start>Messaging>Media Messages>Menu>Options>Account Setup>Media Messages

Menu- Edit connections - Menu- Add

Server: O2 MMS

Download Messsages: automatically

Outgoing message size: less than 100kb

Allowed message types: personal

Menu>Edit connections

Description: O2 MMS

MMSC Address: http://mmsc.mms.o2.co.uk:8002

Data Connection: Secure WAP network

Gateway: WAP 1.0 Gateway

I.P Address: 193.113.200.195

Port: 9201

In Internet explorer, Menu-Options-Connections

Untick 'automatically detect settings'

Make 'Select network: Wap network' (for WAP over GPRS) or 'Select Network: The internet' (for WAP over CSD).

This was copied from another post.. but for the MMS part, u must go to Configurations which is among the menu such as settings, games etc.. right at the end ! and u'll find MMS settings.