Are you running 1.1.2? Did you unlock/activated the iPhone yourself? If you (or whoever hacked your phone) created a NETWORK SPECIFIC plist file to make it work with your network settings, that's the file to delete AFTER installing iWorld.
I'm running 1.1.2... so if you're running 1.1.1 or older, THIS DOES NOT APPLY TO YOU. Install "Services" app so you can turn EDGE on/off
1. Access your phone from your computer (SSH) IF YOU DON'T KNOW HOW TO DO THIS, DO NOT CONTINUE READING. GET SOMEONE WHO KNOWS WHAT THEY'RE DOING TO DO THIS WHOLE PROCESS FOR YOU.
2. Go to /system/library/frameworks/coretelephonyframework/support
3. Find the network specific plist file that MAY OR MAY NOT be in your iphone and DELETE the file. ( I backed mine up first just in case ) As I've mentioned in my previous post, the original hacker of my iPhone CREATED a VFONE.plist file so my iPhone would work with Vodafone IN MY COUNTRY. DO NOT DELETE ANY OTHER FILES. IF YOU DON'T KNOW WHICH FILE OR YOU'RE NOT SURE.... STOP!! DO NOT DELETE ANYTHING. Dunno if you can just copy the file back if it's the wrong one.
4. Make sure you have iWorld installed and pick your country. If not, your phone and sms apps will crash and will not work.
5. Re-boot ( I ran iWorld again for good measure )
Check your network settings. Your EDGE menu should re-appear.