Mick Anderson has a great site at http://www.ia470.com/primer/intro.htm
It is for IATSE Loca 470, but the information within the document is a good resource. The site is very true to the title "Stagehand Primer", with a very diverse amount of information. While many items are geared towards newer technicians, the rigging section is a useful reference for those that do not work with chain hoists very often. It is also a useful look into the structure of IATSE for those that do not often work with the union.