Hi ROS users,

I'd like to announce the differential_drive package.  This provides some of
the low level nodes needed to interface a differential drive robot to the
navigation stack.  I think this will be especially useful for beginning
hobby roboticists like myself, and it provides the following nodes:

   - diff_tf - Provides the base_link transform.
   - pid_velocity - A basic PID controller with a velocity target.
   - twist_to_motors - Translates a twist to two motor velocity targets
   - virtual_joystick - A small GUI to control the robot.


The ROS wiki page (with links to tutorials) can be found here:
http://www.ros.org/wiki/differential_drive

My hacked K'nex robot is an example using this package:
http://code.google.com/p/knex-ros/wiki/ProjectOverview

This is my first released package, I hope someone out there finds it useful.

Thanks,
-Jon