Vox is a mobile VoIP client for Android that will soon break out to other mobile platforms including BlackBerry 10. Expected to launch at the end of 2013 it looks like BlackBerry 10′s VoIP, IM, and video conferencing options are becoming plentiful.
Vox originally launched in 2005 as a competitor to Vonage and has been transitioning to the mobile ever since. By next year they should be running on all cylinders and supporting the top 4 smartphone platforms. The app also has the ability to call mobile phones in certain regions like the UK, Mexico, India, Pakistan and Vietnam.