This page is presented by Princeton University which has completed a study upon centrifuges that is very comprehensive and that I have found to be quite helpful.
http://ceor.princeton.edu/~radu/soil/velacs/

This page is from NASA, the page provides information as to how centrifuges are used to train astronauts and to test equipment bound for space travel.
http://lifesci.arc.nasa.gov/CGBR/cent20.html

This page belongs to a company that sells centrifuges to clean oil using the centripetal forces to remove dirt.  This page shows how centrifuges are employed in commercial uses.
http://www.dieselproducts.com/spinner/spinner.html

This is another page form NASA that talks about how centrifuge technology is being used in the production of Space Station Freedom.
http://ic-wwww.arc.nasa.gov/ic/projects/neuro/centrifuge/cent.html

This site is for a company selling centrifuges that are used for continuous separation of two immiscible liquids having different specific gravities, and for clarification of liquid.
http://www.pennwalt.com/super_c/super_c.htm