Good news, Android App developers! You can probably expect an uptick in sales this month – and not just because of the Holiday bump. Just in time for the season of spending, T-Mobile has begun to roll out carrier billing support for the Android Market, allowing us all to buy up apps by charging them back to our cell phone bills.

Back in November, T-Mobile disclosed that carrier billing was “coming soon”. Flash forward to last night, when a handful of users began noticing that they now had a “Bill My T-Mobile Account” payment option. Not everyone will see the update hit their handsets immediately – in fact, T-Mobile’s giving themselves until December 30th to get it out to all of us. Perhaps frustratingly, there’s no notification if your Market app has been updated; unlike nearly every other Android-related update, this one happens silently. In other words, you get to keep checking.

One odd caveat: If the app you want to buy is sold in euros/pounds rather than dollars, you’ll still need to use a credit card. T-Mobile and Google are still “working on a solution to properly convert these applications into US Dollars”.

[Via AndroidAndMe]