The message from Research In Motion to developers is clear - it's time to start building those BlackBerry 10 apps.

The company has sent out invites to BlackBerry 10 Jam (which we have to say sounds an awful lot like something you might spread on your toast) - a conference that "will allow developers to be part of the initial conversation and learn about the new platform and the evolution of BlackBerry".

BlackBerry 10 Jam will run alongside the big BlackBerry World event in Orlando in May and will be a platform to see and discuss the new OS's strengths and vision. It is a chance for developers to see how they "can make applications that stand out, as well as drive usability and loyalty", RIM says.

Pictures of BlackBerry's new OS 10 were leaked online last month, showing a drastic change to the way that RIM's operating system will look. First up, the home screen has undergone a major facelift, adding what looks like widgets and ideas taken from the BlackBerry PlayBook.

Looking more like a scaled-down version of the QNX interface found on RIM's tablet, it clearly shows a huge change in how BlackBerry mobiles will operate.

Indeed, RIM has also confirmed to Pocket-lint that the existing PlayBook device will be upgradeable to BB 10 when it launches later this year.