How can I get rid of SPAM mail?

How can I get rid of SPAM mail?: "In the fight against spam, Attorney General Lockyer filed the first consumer protection lawsuit on behalf of the state against a California company and two owners/operators for sending unsolicited, commercial emails in violation of state law.
Since 1998, California has prohibited individuals and companies from sending commercial email to those who have neither requested nor consented to receive the email, or with whom they do not have an existing business or personal relationship, unless: The sender has either established a toll-free telephone number that recipients can call to stop future emails or included a valid email address that recipients can contact to stop future emails; and The subject line of the email begins with the four characters 'ADV:' designating it as commercial communication, or 'ADV:ADLT' designating it as sexual, adult material.
"