This is a ROS package which streams data coming from the 3DConnexion 6D mouse. It uses the spacenav daemon for linux: http://spacenav.sourceforge.net/
Once you've added the package to your ROS_PACKAGE_PATH and compiled it using rosmake threeD_mouse, follow the following steps.
First start the spacenav daemon:
sudo spacenavd -d
Then start the ROS interface:
roslaunch threeD_mouse threedmouse.launch
The package will publish geometry_msgs/PoseStamped on the /threedmouse/pose topic. They contain a translation vector + a rotation quaternion.
You can choose to either publish translation only, rotation only or both translation and rotation by pressing the right and left button on the device. You'll see which mode you're in if you open a rxconsole.