Each tutorial is in one or more of the following four formats:
Interactive presentation that can be explored in your browser with the free CDF Player plugin. Can also be viewed and modified using Mathematica 8+.
These are interactive presentations which can be run in Mathematica 5+. Also viewable with the CDF Player plugin, but you won't be able to run them. Try the html versions instead.
Download Acrobat Reader to view pdfs.