T-Mobile has indicated through its support forums that it is bringing carrier billing support to the Android Market. Until now, users wishing to purchase applications had to use Google Check-Out to pay the software developer directly. With this feature enabled in the Android Market, T-Mobile customers will be able to purchase apps and have the expense added to their monthly bills. T-Mobile users will notice their Android Market application update itself. Once the update is complete, carrier billing will be enabled. Users have a 24-hour period to uninstall applications that they decided they don't like before being billed. Users will also have the choice to pay via either their T-Mobile account or with their own credit card. T-Mobile is the first network operator to support carrier billing in the Android Market.

Source: Phonescoop