Anti-Spam Tools and ResourcesMost anti-spam technology focuses on blocking known spam mailers and providing "white listing" where a person only receives email from email addresses they have authorized. Some software packages automate the white listing feature and require they person sending the email to complete a CAPTCHA field to prove they are a human. Many web-based email providers have some built-in spam protection. The downside of white lists provided by web-based email providers is when legimate mail is incorrectly tagged as spam. A lot of spam is generated by zombie machines placed on computers by cyber criminals.
Anti-Spam Resources and Tools
Amazon.com: Spam Fighting Software
BloggersBlog.com: Spam and Splogs: Coverage of spam affecting the blogging industry.
Can Spam Act
Coaliton Against Unsolicited Commercial Email
Fight Spam on the Internet!
FTC Spam -- the FTC's spam website.
Google Spam Resources
HowToWeb Spam News -- coverage of spam-related tech news.
Spam Full Coverage -- Yahoo News
Yahoo Spam Resources
Wikipedia's Spam Entry