[jon1856]

A rather down and dirty search found the following sites with all sorts of definitions, including pinning:
http://www.utsa.edu/sa/greeklife/htm/greekterms.htm
http://www.answers.com/topic/pinning
http://www.usd.edu/greek/sae/recruitment/terms.cfm
http://www.deltachi.org/resources/ot...g_Ceremony.pdf
http://people.howstuffworks.com/fraternity4.htm