American Express, which recently launched its own online payments service for US residents, has now announced a partnership with mobile payment service Payfone. Payfone will combine its mobile authorisation and payment services with Serve, the new American Express payments platform.

Serve already gives customers in the USA a 'virtual wallet' that can be accessed online and via a mobile app.

Mobile consumer research group mobileSQUARED has launched a new database that provides detailed historic data and forecasts for UK and US mobile phone usage. The Mobile Consumer Trends database covers the mobile internet, mobile apps, mobile commerce, opt-in messaging and mobile advertising, with forecasts searchable by device type, gender, age, geography and socio-economics.

MCT's information starts from the fourth quarter of 2009 and is updated every quarter with figures from Lightspeed Research.

RIM has announced a launch date and pricing for its BlackBerry PlayBook tablet. It'll be available in the USA and Canada on 19th April via Best Buy, with a range of other retailers also expected to sell the devices.

There'll be three WiFi-equipped models, from $499 (around £305) for the 16GB version to $699 for the 64GB version.

Amazon has launched its Android mobile application store today.

Known as the Amazon Appstore (although that's not prevented Apple from taking legal action to protect its own App Store), it's currently only available to consumers in the USA.

Big news from the USA. Network operator AT&T has agreed to acquire T-Mobile USA from Deutsche Telekom in a deal that's worth around $39 billion. In addition, Deutsche Telekom will end up owning around 8% of AT&T.

The joint venture will be the country's largest mobile network, approaching 130 million customers.