A step-by-step online tutorial about LHC@home for Mac users by Alexandre Racine.
It contains detailed instructions on how-to-join this volunteer computing project.
There are 3 screen capture videos with the real installation process accelerated attached to the event page.
This 5' video is linked from http://lhcathome.web.cern.ch/join-us
Also from the CDS e-learning category.