According to the tutorial, I should go to OpenSSO and download an "express build". However, the download links on the OpenSSO site for the "Express Build 7" appear to require logging in via an account with a paid support contract.
How can one currently download the OpenSSO wars?
You may want to try OpenAM.
I also noticed this.. http://download.java.net/general/opensso/webstartnew/ which will download the bits for testing. And guess what... there is an opensso.war and the like 'in there' that were produced about the same time as the tutorial was written.