This module re-exports all of the functionality of the CHP library, except the traces mechanism available in the Control.Concurrent.CHP.Traces module.
For an overview of the library, take a look at the CHP tutorial: http://www.cs.kent.ac.uk/projects/ofa/chp/tutorial.pdf available from the main CHP website: http://www.cs.kent.ac.uk/projects/ofa/chp/, or take a look at the CHP blog: http://chplib.wordpress.com/.
You should also look at the chp-plus package, which contains a lot of useful further functionality built on top of CHP.