The following list of resources can help you separate the hoaxes from the valid warnings. (In addition to these resources, there are also several papers in section VII. Papers and Articles that discuss how to identify a hoax.)
• Charles Hymes' Hoaxes
http://www.nonprofit.net/hoax
• CIAC (Computer Incident Advisory Capability)
     Internet Hoaxes--how to identify a new hoax or valid warning, what to do
     http://hoaxbusters.ciac.org/HBHoaxInfo.html
     Internet Chain Letters--how to recognize a new chain letter, what to do
     http://hoaxbusters.ciac.org/HBHoaxInfo.html
• Command Software - Virus Hoaxes
http://www.commandcom.com/virus/virus_hoaxes.html
• Computer Virus Myths home page
Rob Rosenberger's links to computer virus myths, hoaxes, urban legends
http://www.kumite.com/myths/
• F-Secure - Hoax warnings
http://www.f-secure.com/virus-info/hoax/
http://www.europe.f-secure.com/virus-info/hoax/ [mirror]
• ICSA Labs, a division of Cybertrust -anti-virus vendor-independent hoaxs page
http://www.icsa.net/html/communities/antivirus/hoaxes.shtml
• McAfee - Virus Information Library - Virus Hoaxes
http://vil.mcafee.com/hoax.asp
• Panda Software - Virus Encyclopedia - Hoaxes and Jokes
http://www.pandasoftware.com/library/hoax.htm
• Sophos Virus info - hoaxes and scares
http://www.sophos.com/virusinfo/scares/
• Symantec AntiVirus Research Center (SARC) - Virus Hoaxes
http://www.symantec.com/avcenter/hoax.html
• Trend Micro Encyclopedia - Virus Hoaxes
http://www.trendmicro.com/vinfo/hoaxes/default.asp
• Urban Legends Reference Pages: Computers (Viruses)
http://www.snopes.com/computer/virus/virus.asp
http://urbanlegends.about.com/od/internet/a/current_netlore.htm