AT&T Inc. (NYSE: T) has posted a Web page unveiling its new 3G "MicroCell" home basestation, saying that the box is currently available for sale in "select markets."

The "soft launch," first reported by Unstrung last week, means that AT&T is the first U.S. carrier to launch a 3G femtocell, beating Sprint Corp. (NYSE: S), which had said it would be first. Sprint and Verizon Wireless both have 2G femtocells available. (See Look for AT&T's Femto 'Soft Launch' Soon and Sprint: We'll Beat AT&T to 3G Femto.)Home base stations are tiny cellular radios designed to improve voice capacity and coverage in the home. AT&T's device will do the same for 3G data coverage in a user's humble abode, while adding GPS location capabilites.

As expected, the AT&T MicroCell was produced with Cisco Systems Inc. (Nasdaq: CSCO). The initial box is a Y-shaped standalone home base station; Cisco has also been said to be working on a home gateway that integrates a femtocell. (See Cisco Femto Spotted at AT&T.)

Here's what AT&T is listing as the main features of its new box:

The carrier recommends that users install the device by a window to take adavantage of GPS. The box, however, can be moved around by the user, "provided the new location is within the AT&T authorized service area and properly registered online," the carrier says on the page.

The carrier is once again using video to promote and explain the femtocell: A cell-savvy mother walks you through how a home base station can be femto-fun for the whole family.

AT&T has started selling the $150 device in Charlotte, N.C. Early adopters can get a $100 rebate if they sign up for a monthly unlimited call plan. Engadget reports that the carrier will charge $19.99 per month for unlimited calls, or $9.99 per month for unlimited calls if a customer already has a fixed line or Internet service with AT&T.

— Dan Jones, Site Editor, Unstrung