As a consequence of the swine flu, the miracle disinfectant Purell has been getting a lot of press. Masks aren't going to do you much good, if articles such as
this one from the New York Times are to be trusted, taking Tamiflu before you get theflu isn't to be recommended, unless you like multi-drug resistant superbugs¹, but washing your hands (not just running them under the water, but giving them a good rub with soap) is still the easiest way to combat disease.
¹And as a recent infectee with a drug resistant superbug, I can assure you that you don't.