Research In Motion is not expected to release its next generation BlackBerry 10 handsets until the first quarter of 2013, but the company has something for its loyal users in the meantime: free Wi-Fi calling over BlackBerry Messenger. Version 7.0 of the popular messaging platform has just entered beta with a new feature called BBM Voice that will could provide a simple way for users to save on voice minutes.

The new feature is tightly integrated into the platform. BlackBerry Messenger will show who in your contact list is available to call using BBM Voice, and a simple press of the dial key will send a request to start a voice call. During calls users can jump into a split screen mode allowing them to talk, text and send images or other content at the same time with any BBM contact, or even switch to other applications.

BBM has long been touted as a key advantage of BlackBerry devices over the competition. And though it was quite disruptive at the time, similar cross-platform options like WhatsApp have since cropped up to lessen its appeal. The ability to make free calls over Wi-Fi is not new either, as applications like Viber have been doing that for a while and even support cellular data connections. Nevertheless, having the option baked into the OS presents some advantages, and might be a big deal in emerging markets where BlackBerry is still strong.

Although the ability to make free voice calls may sound as something that carriers would frown upon, it appears that they’re willing to play ball as long 3G/4G support remains out of the picture. James Tantram, senior product manager at RIM, tells The Verge that carriers believe BBM drives a lot of purchase decisions and making it more compelling means more people will want to sign up for the BBM plan or data plan.

BBM 7 with the new BBM Voice feature is currently available in beta form for BlackBerry smartphones running BlackBerry 6 OS or higher, with support planned for smartphones running BlackBerry 5 OS at a future date. The beta can be downloaded for free from BlackBerry Beta Zone.