Possible Duplicate:
How to disable Mobile Data on Android
I know that this is possible in version 2.2 and below but since 2.3 it is not possible, unless you have a application that has a certificate supplied by google that specifies it as a secure application or if you place your application in the /system/app directory. I have attempted to place the application in the system/app dir and found this to be impossible on the emulator even with su rights. How would I make my application secure for android market (so google will give me the certificates required) or install the application to the system/app dir. The only other possibility is to use the ndk, but i am not so sure if it will work and the time and effort that would have to go in to hack around this will just be a pain. Can some one assist in the problem.
Disabling 3G using methods provided by the SDK is not possible, anyway I think I remember a solution where the APN was set to a invalid one to kind of disable 3G
EDIT:
I just figured out that APNDroid uses exactly this renaming-workaround to disable the 3G connection.
Here you can browse the source code of the application