Scambusters
Is it possible to stop spam? probably not -- but you can significantly reduce it.
http://www.scambusters.org/stopspam/index.html
Samspade.org
Samspade.org
http://samspade.org/
SORBS.net
Sorbs anti-spam email blocking and
filtering system. tips and tricks for closing open proxy servers,
along with useful tips for configuring smtp mail servers.
http://dnsbl.sorbs.net/
SpamCop
Beware of cheap imitations! spamcop has been protecting the internet community since 1998. automatically file spam reports with the network administrators who can stop unsolicited email at the source. subscribe, and filter your email before it reaches your inbox.
http://www.spamcop.net/
Spamvrij.nl
Spamvrij.nl
http://www.spamvrij.nl/
Spamlaws
Spamlaws
http://www.spamlaws.com/
Symantec
Symantec
http://search.symantec.com/custom/nl/query.html