According to Dr. Lapp, Tamiflu and Relenza are currently preferred because resistance has developed to the other antivirals. 

There is also a homeopathic remedy available at most drugstores called Oscillococcinum that some people swear by to reduce the symptoms and duration of the illness.  As with many homeopathic medicines, there is a debate as to its effectiveness.  While a few clinical trials have suggested that Oscillococcinum can reduce the duration of the symptoms of flu, some researchers question the statistical significance and the scientific rigor of these studies.    

Sources:

Lapp, Charles W. (2007, February). Influenza Vaccination., From Hunter-Hopkins Center Web site: http://www.drlapp.net

Lowe, John C. (2003, December 7). Should You Get a Flu Shot?  From drlowe.com Web site: http://www.drlowe.com/emailnewsletter/2003archive3.htm