I just got a unlocked and jailbroken iPhone 4. It has version 4.0 and modem firmware 01.59.00 for the life of me I cannot get data or mms to work. I dont have the option to edit network so cannot manually enter the Simple Mobile information. I need help as to what I need to install to get that button to appear so that I can edit the network info. Any help and walkthrough would be greatly appreciated.

Thanks

Have you installed any carrier profiles or carrier bundles? Many are available in Cydia and can resolve the issue without manual editing of the APN settings. Aside from that, the ability to edit the APN information is blocked by default and you'll need to enable it.

A mostly helpful post about this is available here:

How to Set iPhone 4 APN One Step

Good luck!

I know that it sounds strange, but install iphonedelivery.... see Advinux - IphoneDelivery

This seems to enable the correct carrier settings and solved the same problem for me

Spants