Need another watering can to irrigate those crops on your highly-profitable Facebook farm? Soon you may be able to boot that expense directly to your monthly mobile tab, just as you do with other necessities, like ringtones and emoticons. The social networking site is working with carriers to streamline billing, eventually enabling Facebook users to pay their app dues along with their monthly phone bill. Naturally, this is a win for developers, since eliminating the need to pre-purchase Credits or enter card information will result in an increased number of impulse purchases -- and let's face it, there's no line item for FarmVille in the monthly budget. Quite a few carriers appear to be on board -- AT&T, T-Mobile and Verizon in the U.S.; Deutsche Telekom, Orange, Telefonica and Vodafone in Europe; and KDDI and Softbank in Japan -- so it looks like devs should have plenty of reasons to celebrate. The service will be automatically activated once providers support it, enabling easier purchases for "hundreds of millions of people worldwide." Streamlined carrier billing is but one recent development, so hit up the source link for the full rundown.