Mobile commerce technology provider Usablenet Inc. has teamed with eBay Inc.’s PayPal to integrate the online payment company’s Mobile Express Checkout with Usablenet m-commerce sites, mobile apps, tablet apps, Facebook applications and kiosk systems.

Consumers with PayPal accounts enter their user name and password and then buy with one touch; the system uses the consumer’s stored default shipping and billing information.

Usablenet sees a vast opportunity in the partnership. With more than 90 million active users worldwide, PayPal reported in Q3 2010 a 26% increase in online payment volume growth compared with Q3 2009, a portion of which was attributed to mobile transactions. Over the 2010 holiday shopping season, from Nov. 15 through Dec. 15, PayPal experienced a 300% increase in mobile payments volume and closed out 2010 with $750 million in mobile payment volume, the company says.

Usablenet clients include nearly 200 Fortune 1000 companies, it reports. Clients include Amtrak, American Airlines, ASOS.com, Crutchfield Corp., Delta, The Estee Lauder Cos. Inc., FedEx, Hilton, J.C. Penney Co. Inc., JetBlue, Marks & Spencer, Sprint and Victoria’s Secret.

“Usablenet empowers top e-commerce merchants throughout the world,” says Bill Zielke, PayPal’s senior director of merchant services. “By integrating PayPal’s Mobile Express Checkout with Usablenet’s offerings, businesses can enable consumers to speed through checkout securely using their mobile phones.”

Founded in 2000, Usablenet is a private company headquartered in New York with offices in London and Venice.