Unless you carrier supports tethering, you really cannot without modifying carrier settings - and tethering outside of your contract agreement runs the risk of having your contract voided and disconnected.
Unless you carrier supports tethering, you really cannot without modifying carrier settings - and tethering outside of your contract agreement runs the risk of having your contract voided and disconnected.
You can no longer install a hacked carrier file without jailbreaking. 3.1 implemented a signature check when installing .ipcc files. You have to jailbreak to disable this signature check and allow these files to be installed.
I would like to point out that jailbreaking is not hard or dangerous at all, and does not by itself slow your phone down. You could just jailbreak, install a carrier hack to disable the signature check, and install a hacked .ipcc from BenM.at. You wouldn't have to install anything else, and you wouldn't know it was jailbroken if you hadn't done it yourself.
Can't say that's 100% true but I did hear some reference to watch out for this from MuscleNerd (one of the iPhone JB devs) twitter posting. Just don't be a jerk and abuse it by consistently watching HD movies or other bandwidth intensive tasks. Make sure to also to watch your bandwidth usage monthly and adjust your usage to it. From what I heard, the unofficial data cap is 5-6GB for AT&T.