Hoax Checkers

I typically check

www.hoaxkill.com first,

Then if I don't find what I need I go to about.com and check their sites:

   http://antivirus.about.com/msub2.htm (for virus hoaxes)

    http://urbanlegends.about.com/   (for urban legends.)

http://www.symantec.com/avcenter/hoax.html  (a more authoritative list from the people who make anti-virus software)

http://kumite.com/myths/ (one of the best anti-virus and anti-hoax sites)

 

Maybe

www.urbanlegends.com  

http://ciac.llnl.gov/ciac/CIACHoaxes.html but they are not as well laid out and comprehensive as the others.