Verizon Wireless and American Express announced today that are joining forces to offer mobile payments using one’s cell phone number and a pin number as authentication, rather than a credit card number.According to AllThingsD.com, 100 million Verizon subscribers will be able to use the new service to shop on any Internet-connected device, including a PC, phone or tablet. Subscribers will have to sign up for a Serve account through American Express, which can be funded by any bank account or credit card.One potential hurdle is that online retailer will also have to integrate Serve in order to take these payments. These various steps could make the road to widespread adaptation bumpy.”Yes, they have to be Verizon and a Serve customer, but we are preloading a number of devices – smartphones or tablets – with the Serve app, and when you preload there’s a much greater uptake,” said Dan Schulman, group president, Enterprise Growth, American Express.Amex’s deal with Verizon isn’t exclusive so American Express could be partnering with other mobile companies soon.If you’re interested in learning more about credit card processing and accepting mobile payments for your subscription site, we have a collection of great payment processing resources at our sister site SubscriptionSiteInsider.com