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.

Research from the Internet Advertising Bureau and PwC shows that the UK mobile advertising market grew 116% year-on-year in 2010, with a total of £83 million being spent.

Although entertainment and media brands have dominated mobile ad spending in recent years, the report shows this dominance is reducing as other advertisers are seeing the opportunities of mobile advertising.

Ofcom has announced plans to auction radio spectrum that'll be used for 4G LTE and WiMAX mobile phone services.

It'll be auctioning two spectrum bands; the old analogue TV bandwidth at 800 MHz, along with a higher-frequency band at 2.6 GHz. Together, these bands are equivalent to three-quarters of the mobile spectrum in use today - and are 80% more than the 3G auction that took place in 2000.

Mark Bridge writes:

The Terminate The Rate campaign has pretty much run its course. Its aim was to get Mobile Termination Rates reduced. These are the wholesale charges paid when a mobile or fixed-line network connects a call from one of its customers to a rival. Lower MTRs would mean better deals on call charges, the campaign argued.