Just to recap the goals of the project for the sake of this thread.
As part of normal life processes proteins "fold", folding at home aims to study this phenomenon through the use of computer simulations. If you participate you are donating your spare computer cycles to that end. The folding at home client runs in the background on your computer at a very low priority so it will never slow down anything else you are doing, it does most of its work when you aren't doing anything.
The benefit of the project is that it should dramatically increase understanding of how, why, and when proteins misfold. Protein misfolding causes several diseases including BSE, alzheimers, and several forms of cancer.
The faq at the FAH site is excellent and should clear up any concerns, questions anyone would have about running the program. To the extent that people have questions the faq doesn't answer, pm me and if I can't answer it I will try to find the answer.