Are any carriers known to charge extra for this tethering? I see that on the FAQ that it says depending on the carrier you may incur additional fees, but has anyone actually experienced their carrier doing this?
Charges from carriers supporting Android phones
Our main feature is that we try to make our tether go undetected, or only detectable as regular phone usage. In the case of regular internet usage web browsing and e-mails you should be able to go completely undetected in our android version as this will just appear as if the android is accessing the internet through its web browser.
We offer no guarantees on this, because we can only assume the most common possible methods of Tethering detection, and some carriers may have in depth detection methods. Like scoping all HTTP Requests from your phone for the browser agent, and then charging you for Tethering on any browser data that doesn't come from the default android browser.
But with all the potential apps out there for mobile devices these days. Detection as stated above would cause a lot of support issues from users trying new web browsers etc.. on their phones.
So many carriers instead rely on working with Tethering solution developers to implement more blatant detection methods. We've seen Blackberry's IP modem solution provide such information.
And it is suspected, if not already discovered, that the default Android 2.2 Tethering solution will be the same.
Quoting you TIm: "Like scoping all HTTP Requests from your phone for the browser agent, and then charging you for Tethering on any browser data that doesn't come from the default android browser."
This avenue would be highly unlikely as there are many Android browsers available in the market, even with the default Android webkit based browser you can change the browser agent to appear as a desktop based browser.
We really have no way to know what detection methods are available to them (the carriers).
If you try to Tether with Froyo (Android 2.2 built in wired solution) you will be detected by your carrier and taken to a webpage relating to your attempt to tether, much like what happens when attempting to tether a BlackBerry over DUN with the BlackBerry Desktop Manager. (on some carriers)



I know for a fact that, and let me stress, _at this point in time_ T-Mobile will not charge for tethering.
I do however know that AT&T will. They do infact have a feature ($25-$30 I believe) so they will charge you if they see that you are doing it without adding that tethering feature.