AT&T announced its new mobile data sharing plans last month that allows customers to share data between their phones and tablets while also allowing families or businesses to share data across their devices. Adding to the announcement, AT&T just announced this morning that the plan would be available to its customers Aug. 23. The carrier provided a tool for families to calculate just how much data they need, offering from 1GB to a whopping 20GB of data. Here is the cost matrix:

Sadly, you need an activated smartphone to use a shared data plan. It is disappointing you cannot go data only, because just being able to buy shareable data for a few iPads and Macs would have been useful. Will this save any of you money? I think it comes down to personal use.

Verizon announced a similar plan in June that allows users to share data with up to 10 devices through a single account. Verizon also offers a similar calculator so customers can decide what is right for them. [AT&T]