One of the major improvements in the iPhone 3.0 Firmware is the launch of the MMS Service. Though iPhone 2G users would not be able to use this but iPhone 3G and 3GS users can use this facility on their phones.
I recently upgraded my iPhone 3G firmware to the latest 3.0 version but I was disappointed to see that the MMS feature was missing from my handset. I did see the Messages settings but the above screen was missing.
I recalled that this feature is available to my phone and also my country (India) so there must be something that I forgot to do.
The MMS feature would be available on the SMS and Photo wizard as shown in the following screenshots.
Steps to fix the problem:
1. So this was how I solved my problem
First make sure that your carrier supports the MMS feature, visit this link
2. Now reconnect the phone to the iTunes. A notification will pop up which want you to update your Carrier Settings. This is important since your carrier has updated its settings with the launch of MMS.
3. Reboot the iPhone.
The MMS feature will appear now on your 3.0 upgraded iPhone 3G.