I've been doing builds of ROS for ARM now, and I'm pleased to announce a 
more complete build of ROS Hydro for Ubuntu 13.04 armhf.

This includes builds of the core ROS tools, along with OpenCV, PCL and 
Navigation.

Install instructions are here: 
http://www.ros.org/wiki/hydro/Installation/UbuntuARM ; I've tested and 
confirmed that they work on my BeagleBone Black

Enjoy!
-Austin