Update: AT&T has clarified this leak for us, saying you can upgrade to a 4G phone and keep your current unlimited plan. You can find an updated post here.
Anyone planning of getting a new Inspire 4G, take note. This internal document from AT&T might weigh heavily in your decision. While AT&T has decided they won't be charging more for their 4G service, they will require anyone using a 4G device to get a new plan.
According to the memo, the data tiers for 4G are the same as the 3G plans, namely $15 for each 200 MB or 2 GB for $25.00 (with $10 per GB overage). This means unlimited data in no longer an option, because you will have to change plans. We have no idea how this will affect customers with unlimited data grandfathered in who buy a phone off-contract and just drop their SIM card in, but I would imagine AT&T can tell with a little bit of auditing. Will this affect your buying decision? Sound off in the forums! [via the Android Central app]