Here are a few stories covering this topic if you care to read up/skim before going further. http://www.businessweek.com/ap/financialnews/D9G30GCG0.htm
http://mashable.com/2010/06/02/att-kills-ipad-unlimited-data-plan/
Much like the ETF open letter that was available from AT&T it really doesn't spell out everything. Also, I'm not a fan of AT&T in any way. I currently am evaluating my options to get away from AT&T to Verizon with an Android phone of some flavor.
Existing Customers - AT&T has decided to change their fees for data plans. Anyone under contract with AT&T will be able to keep their previously agreed data plan as long as they have a contract with AT&T.
Quote from BusinessWeek Article - "Current AT&T subscribers will be allowed to keep the unlimited plan, even if they renew their contracts. But all new subscribers will have to choose one of the two new plans."
So if you are already have an iPad 3G or iPhone then you have no worries as long as you have that plan or upgrade to a new plan with a new iPhone or data package.
New Customers - New iPad 3G and iPhone customers have to choose from the new data packages only. Unless AT&T backtracks or Apple has a fit, this will be the new plan fees going forward for any new customer. $15 for 200MB of usage and $15 for ever extra 200MB which AT&T claims will work for 65% of their iPhone customers. $25 for 2GB and $10 for every additional 1GB. This will according to AT&T will be sufficient for 98% of their iPhone customers. (information pulled from BusinessWeek Article listed above)"With that plan and voice service, a smart phone could cost as little as $55 per month before taxes and add-on fees, down from $70 per month" - BusinessWeek Article. This will allow lower end users to save money and makes me think we will see a new lower cost iPhone. This will get the iPhone into more hands since Android has overtaken them with total handsets. We will see if that is true at WWDC next week.
Overall, taking away the all-you-can-eat data plan from iPhone is not as traumatic as it is for the iPad. This could very much slow down sales and possibly change how people really want to use the iPad. The iPhone should be ok with this change because it's hard to use 2GB of data in a one month period, in my opinion. I'm still going to pay $30 for unlimited because I like the all-you-can-eat format better for a phone.
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