The first obvious thing is to report and complain about SPAM.

Next is to vote with your wallets; don't use companies that send or allow others to send SPAM or advertise their products by SPAM.

Then do the usual things: write to your local MP (or equivalent) to try to get stronger anti-spam legislation.

Other ways to support the fight against SPAM and to make your voice heard include joining the 'Coalition Against Unsolicited Commercial Email' at www.cauce.org there is a particular European branch if you are in the UK.

You could sign politik digital's petition against SPAM.

Their is LOADS of information at: abuse.net