Research In Motion (RIM) has officially opened its BlackBerry App World online store, delivering a broad mix of personal and business applications for users of its BlackBerry handsets. These will include a newly announced Skype client for BlackBerry.

BlackBerry App World is available to users in the UK, the US and Canada from today, with further territories to follow, RIM said.

The service requires users to download and install a BlackBerry App World executable to their handset in order to browse the available applications. Only BlackBerry devices with a Pearl trackball or SurePress touch screen are supported, but this includes most models launched over the past few years.

Once installed, BlackBerry App World automatically presents the relevant catalogue of applications available for the specific BlackBerry handset the user is operating, according to RIM.

As well as a front page carousel showcasing a selection of applications, App World lets customers search the available selections by keyword, and read reviews by other users.

App World also includes a folder called My World, which tracks the applications that users have downloaded, allowing them to reinstall applications or transfer them to a new BlackBerry device.

While the BlackBerry App World executable is a free download, the applications listed online will be a mix of free and paid-for software. Customers will need to sign up for a PayPal account in order to purchase applications.

In a separate announcement, Skype said that it will make a BlackBerry version of its Skype IP telephony client available through the App World service.

Due in May as a beta version, this will initially support only the BlackBerry Bold and BlackBerry Curve models, with support for other devices later.

Although only a 'lite' version, the BlackBerry client will support core Skype functions, including the ability to make free calls to other Skype users anywhere in the world, presence, instant messaging, and the ability to make calls at low rates to landlines or mobile phones.

BlackBerry users can download the executable direct from their device from www.blackberry.com/appworld/download.