Jetpack has been picking up the pace with its development lately. Version 1.8 introduces a new module that gives any WordPress site a mobile theme. This module provides a quick way to optimize your site for mobile viewing, especially if you’ve opted not to use a responsive WordPress theme.
The design for the mobile theme may look familiar to you, as it is based on the Twenty Eleven default theme.
Configuring the Mobile Theme module is a little more involved than most Jetpack modules, especially if you need to adjust your sidebar ID, but it’s all outlined in the documentation.