The OpenNI tracker broadcasts the OpenNI skeleton frames using tf. For more information checkout the ROS Wiki: http://ros.org/wiki/openni_tracker
#NITE Information
The NITE library must be manually installed for openni_tracker to function. The two versions that are compatible with this package are 1.5.2.21 and 1.5.2.23.
NITE v1.5.2.23 can currently be downloaded from http://www.openni.ru/openni-sdk/openni-sdk-history-2/