Continuing with its plan to offer subsidized netbooks and locking customers into long-term 3G data plans, AT&T will begin offering the 10-inch Acer Aspire One netbook through a partnership with Costco. Employees are currently being trained for the launch, which, according to Boy Genius Report, should take place on May 11.

The machines are expected to become available from both AT&T retail stores and Costco electronics kiosks. The company is already offering a subsidized 8.9-inch Aspire One through Radio Shack for the small price of $79.99 – coupled with a lengthy and expensive 3G contract of course. Still, if you were thinking of getting a data plan anyway it is a nice deal. No word on how much the 10-inch model will cost but we should find out soon enough.