PayPal got its biggest break in mobile yet when Research In Motion launched the BlackBerry App World in April, and chose the company to be the exclusive billing provider for the storefront.

But clearly, the eBay-owned company doesn’t want to stop there. PayPal’s Fabio Sisinni, who is in charge of PayPal Mobile’s go-to market strategy, told me in April: “We are investing more in mobile. We see the market opening up…BlackBerry is the first step, you will see more news from us.”

While he was reluctant to provide details at the time, yesterday PayPal said it has launched its latest mobile product—an application for Google’s Android operating system, which gives users access to their PayPal account right from their phone. Not only does it allow users to see recent transactions and check balances, it also does things inherently mobile, like integrate into your contact list, so “you won’t need to remember people’s numbers or emails anymore to send them money.” The company launched an iPhone application some time ago.

PayPal is worth watching in the mobile space. It has built out a robust, secure payment solution that works across multiple countries and currencies. It also has a large consumer following. All of those things could make it attractive to developers, who would find it easier to work with PayPal than individual carriers. But carriers can’t be ruled out, either. RIM (NSDQ: RIMM), Microsoft (NSDQ: MSFT) and Nokia (NYSE: NOK) are all in talks to integrate carrier billing into their mobile app stores. However, that didn’t concern Sisinni. “We are confident that we have the best and most flexible platform. We have a lot of plans to improve the user experience.”