Just because you read something on a web page doesn't mean it is true.  Even if a friend sends you an email, it still may not be true.  In fact, it probably isn't.  Here are several places that work to separate fact from fiction.  Check here before you forward it to all your friends.

Snopes

The comprehensive reference listing of urban legends.

CIAC Security Site

US Dept of Energy Cybersecurity site.  If it really is a problem, they will post it.

Hoaxbusters

CIAC hoax & chain letter information site.

Urban Legend Combat Kit

Suggestions on helping to debunk internet urban legends.