[imdarkside]

If you have unlimited internet I can see why you wouldnt be charged for data. but to have internet through your phone carrier and not be charged via a reg edit or rom upgrade is interesting. are u sure you are getting internet for free?

if that were the case then you would have internet on your phone through the rom upgrade or reg edit everywhere not just when tethering. without wifi, the phone accesses the internet through the cell towers. and for them to not charge you is hard to believe. i suspect you have unlim data.