US operator T-Mobile has extended its existing carrier billing service so that its subscribers can add a wider range of digital purchases to their bills. The operator has offered carrier billing for purchases from the Android Market for two years but will now expand the same approach to purchases from what it says will be “virtually any online source” and across a variety of mobile devices. The additional capability, which will be available from later this month, increases the range of digital goods such as games, social networking credits, music and video that the operator’s subscribers can buy and add to their phone bills. In addition to smartphone and tablets, the move applies to purchases made by T-Mobile subscribers via PC and netbook. Carrier billing supporters argue that its key attraction for users is ease-of-use. They do not have to bother with the manual entry of credit card details, particularly fiddly with a mobile handset.

T-Mobile has relationships with a number of service providers so its users can access carrier billing services. Initially the expansion will apply to those billing services offered by BilltoMobile, Boku, OpenMarket, Payfone and Zong. The operator says additional billing partners will be added as the rollout continues. Rival operator Verizon Wireless linked up with Payfone two months ago to offer the same kind of service as T-Mobile.

Brad Duea (pictured), T-Mobile’s senior vice president of value added services, said the move was part of the operator’s ambition “to be in the forefront” of the expanding mobile purchasing market.