I receive Security Tips from the government's US-CERT list United States Computer Emergency Readiness Team [worth signing up for Cyber alerts - US-CERT] and the following just came in, how to prevent or cut down on those hoaxes and urban legends that are spread through emails from 'friends' - Basically, don't forward chain emails on, but if you really feel you must, check it out first - even from reliable sources you'd be surprised how often the content is an actual hoax/urban legend.
You should read the full email [on US-CERT site] but for now here is where to check out those chains:
If you want to check the validity of an email, there are some websites that
provide information about hoaxes and urban legends:
* Urban Legends and Folklore - http://urbanlegends.about.com/
* Urban Legends Reference Pages - http://www.snopes.com/
* TruthOrFiction.com - http://www.truthorfiction.com/
* Symantec Security Response Hoaxes -
http://www.symantec.com/avcenter/hoax.html
* McAfee Security Virus Hoaxes - http://vil.mcafee.com/hoax.asp