In the absence of a vaccine, the only defenses we have against the spread of H1N1 are simple ones. Cover your mouth when you sneeze or cough (with your arm, not your hands, to avoid spreading the virus through handshakes) and wash your hands frequently. Buy a pocket-sized bottle of hand sanitizer and use it — it's the easiest way to avoid getting sick.
But when it comes to slowing the overall spread of a pandemic flu, the best thing we can do is keep sick people away from everyone else. It's called "social distancing," and studies of the deadly 1918 Spanish flu showed that cities that instituted distancing measures quickly suffered lower death tolls than cities that did nothing or reacted slowly. So if you're feeling sick, don't go to work until you feel better — even though that may not be the most welcome advice for the nearly 50% of private-sector workers in the U.S. who don't get paid sick days.
Read "How to Deal with Swine Flu: Heeding the Mistakes of 1976."