I have a couple Q's,I just got my Inspire rooted I guess it is using the stock ROM (Android version 2.2.1)I am trying to tether it to my Laptop,do I need a custom ROM or App for AT&T not to see that its tethered? or can I just turn on the hotspot?
If you are rooted or not they can still tell you are tethering.
This was explained in another thread but I will try to paraphrase to the best of my understanding. When your phone uses edge/3G/4G it has a certain number it sends to tell how many devices the connection has ran through. Your phone will always give the same number.
When you tether the connection goes from phone to laptop to phone and then to AT&T so they will see this number lower than before. Thus they will know you are tethering (even if you use a completely different app than AT&T tethering app and are rooted.)
AT&T has already sent out emails to a number of people who were tethering telling them pretty much to stop or "We will add tethering to benefit you" kind of crap.
As far as I know you don't need a special ROM to tether, just a rooted phone and an app (not sure what the app is). Just a fair warning that you could still be found out and charged a tethering fee.