Canonical – Ubuntu guys – have demonstrated the Ubuntu Phone OS, a new mobile OS to come in late 2013 or early 2014 that will mimic Ubuntu on desktops.
Here Mark Shuttleworth is showing an app running on phone, it seems neat : http://www.youtube.com/watch?v=RO7QbCqFY7Y&feature=youtu.be
Natively QML with C/C++ and HTML5 with Javascript seem to be the supported languages for creating apps.