A number of free apps offer some useful features to help you prevent or deal with the flu:
The Centers for Disease Control and Prevention's flu app, designed for health care providers, includes consumer-friendly diagnostic tools and vaccination recommendations, flu news, and information about flu activity across the nation.
The agency also recently challenged techies to use its wealth of flu information to develop an app to educate the public. Check out the winners of the Flu App Challenge.
With FluF.A.C.T.S., you can track flu activity in your area, refer to a symptoms finder and prevention tips, and learn what to do if you've been exposed.
Flu Near You uses your zip code to report flu activity near you. With its vaccine finder, you can locate a place nearby to get a flu shot.
If you're looking to find someone to blame for your flu infection, check Facebook's Help, my friend gave me the flu. If you don't have the flu, you can track those who are most likely to get you sick so you can avoid them. The app might not be particularly scientific or accurate, but it is pretty fun.
On the horizon: an app that converts your smart phone into a thermometer. Until then, check our review of thermometers.
Read more of our advice on preventing and treating the flu.
And if you're in the market for a new a smart phone, check our buying guide and Ratings.