Applications purchased on the Android Marketplace for phones running Google’s Android mobile operating system can now be charged to AT&T phone accounts and paid for whenever users pay their bill normally.

The change could help application developers by making it a little easier to pay for an app and get it as quickly as possible. iPhone users link credit cards to their iTunes accounts and are able to purchase an app by basically pressing their screen once. Google earlier relied on Google Checkout to purchase applications, which turned some people off from buying applications.

Google is promoting the new option as a way to help solve the nightmare that is application discovery on the Android Marketplace. There are more than 100,000 applications on the Android Marketplace today. That makes it incredibly difficult to find a new applications. Google also recently revamped its Android Market app to make it easier to browse through applications and discover new ones.

It’s also a good boost for carrier billing evangelists. Carrier billing has become a little more popular as a way to encourage people to purchase new applications by making it easier to do so. There are also a number of companies that want to rely on carrier billing for everyday things and microtransactions and kill off credit cards and other forms of payment, like Boku and Zong.

At least a few people — investing titan Marc Andreessen included — want to consolidate their spending activities to their phone and kill off credit cards and cash. There are a number of ways to go about doing that, like adding a new way of using transaction provider PayPal. Carrier billing is another way.

Google earlier enabled carrier billing for apps on the Android Marketplace on T-Mobile around the same time last year. Android users on Verizon are still out of luck, as carrier billing hasn’t been enabled on that service provider yet. The Android developer blog didn’t say when — or even if — Verizon would enable carrier billing, but it said that Google would continue to work with carriers to help ease purchasing on the Android Marketplace.