Beginning this Sunday, January 22, AT&T will begin offering new data plans to its US smartphone and tablet customers, its first change to the plans since June 2010.

The new plans aren't designed to save money for existing smartphone customers: the previous entry-level Data Plus plan, which offered customers 200MB of data a month for $15, has been replaced by a Data Plus plan that offers 300MB for $20, a $5 increase for just a 100MB increase. The hike is less ostentatious for the middle and top tiers: the DataPro 2GB ($25) and DataPro 4GB ($45) plans have been replaced by DataPro 3GB and DataPro 5GB plans that run $30 and $50, respectively, which is in line with the company's $10/GB overage charges. As with before, tethering and mobile hotspot capabilities are only available for the top tier (5GB) plan.

The story is similar for tablet users: there are 3GB and 5GB Data Connect plans available for $30 and $50, while the price and data cap remain the same for the $14.99 250MB plan.

Current AT&T customers can elect to stay with their current plans, which was the case when AT&T stopped offering unlimited data plans to new customers, but new subscribers will only be able to choose from among the new plans. For current customers, the new plans make sense only for 2GB and 4GB subscribers who regularly go over their caps - an extra GB for $5 is more attractive than an extra GB for $10. Otherwise, I'd recommend sticking with what you've got.

Source:AT&T