PayPal has confirmed its ambition for a leading role in the mobile market with a number of announcements at its second annual developer conference in San Francisco. The company, which says it will handle more than US$700 million in mobile payments this year, launched Mobile Express Checkout, a service that enables users to make purchases with as few as two clicks from their mobile handset. Users remain logged in with PayPal even while browsing elsewhere. The service was previously in beta. Among its other announcements was the addition of a location-based feature to PayPal’s existing iPhone app and new functionality for its Mobile Payments Library. Also at the conference, PayPal parent eBay showed its own mobile intent by announcing its participation in a US$9 million financing round for Appcelerator, the developer tools company which in turn said it is partnering with PayPal.

In a separate development in the mobile payments space, American Express has hired two former Sprint Nextel executives to work in its online and mobile payments unit, Revolution Money, a sign that it wants to catch up rival payment networks Visa and MasterCard, both of which have been more active in the mobile space. Mobile operators are also offering competition in the shape of an alliance between AT&T, Verizon Wireless and T-Mobile USA. The three US operators are partnering in a mobile payments initiative with credit card company Discover. Amex’s new faces are David Messenger, former corporate development officer with Virgin Mobile, the MVNO owned by Sprint Nextel, and Peter Lurie, the former general counsel at Virgin Mobile.