I've been an AT&T customer for a long time. I have been using the iPhone 3G unlimited data plan ($30) for years and now that the iPhone iOS 4.3...

It is true, AT and T have accepted the Internet tethering feature of iOS4.3. Thus, allowing users to create wireless hotspots for up to 3 users.

To activate this feature on your iPhone 4 you need to pay an extra $20 on your contract, and have an iPhone running iOS4.3. Once you are signed up, using the feature is simple to start under the settings menu.

However, Internet tethering has been around for years in the with MyWi/cydia scene. Although, to do this it does require jailbreaking- but, It would save you a significant amount of money.

If you are interested in this, I can outline a detailed 'how to'.

You can't update to latest firmware through iTunes without wiping the jailbreak. Therefore, you become 'stuck' on an iOS if you don't want to have to rejailbreak.

If it is sent in to Apple on its warranty, and is jailbroken they will void the warranty(However, you can easily wipe the jailbreak before taking it in through a restore with iTunes).

Yes absolutely true, one of the problems is that the new iphone comes with features like tethering and video chats...this will greatly increase your internet usage and ATT knows this, so its almost safe to assume they are saying "haha, they are stuck with us and have no other choice if they want to keep their sweet iphones. so we will screw them into paying crazy amounts of data overage charges" and with this being the only country that has the iphone that is doing this to it's customers and not giving them a decent alternative...i can see where this guy is coming from..free market lowers the prices of other carriers but doesnt allow the option to take YOUR IPHONE to that other carrier..you cant move to a different carrier with your iphone..people dont chose the iphone because they WANT to tolerate the caps..its cuz they are forced to and realize the the iphone, the gadget itself not the carrier, is one of if not the best out there.

And if you are looking for jailbreak then move ahead:

Redo the jailbreak and add cydia. Add rock entensions to download mywi which is $10 I think, but is the best tethering app IMO. There are other tethering options you can try in Cydia as well, but you need Cydia for a tethering hack.