Are wireless carriers preparing to increase data fees?

Talk is cheap, at least if you consider how AT&T and Verizon Wireless have recently chopped the price of unlimited nationwide voice calling plans from $100 to $70 a month. But there's concern among critics that these price drops are part of a secret plan to increase data access rates later, given the shift in cellular usage from voice to data for which the iPhone is the poster child. Already, data users are exposed to extraordinary charges if they use more than 5GB per month, paying from $200 to $500 more per 1GB of data above the 5GB limit. And AT&T just added a new fee on users of a category of phones called Quick Messaging Devices; they must now pay a minimum of $20 a month on top of voice plans for some combination of texting and data plans. The previous minimum on such users was $5 a month for 200 text messages, according to AT&T.