Now is the time to update your resume.

The other advice you've recieved is good, and I would suggest working to mitigate the damage without personally sabotaging the SPAM runs. I'd be wary, however, of reporting your servers to any blacklists--you may get yourself sued. If you are harvesting email addresses, you might make sure some cauce.org addresses get on the list ;).

If your boss is a sleazebag and won't stop SPAMMING, try talking to his boss. Focus on the business side of why this is a bad idea. Businesspeople care about money and little else. You will need to be able to show that SPAM will cost your employers more than it will make them. Check out CAUCE

If you are asked to do something unethical once, you will be asked to do so again, so leave as soon as possible. If your boss is reprimanded, it may be possible for you to stay, but even then he is likely to blame you for his problems.

If your employer does not cease spamming before you find other work, you can offer to 'help' by updating the job description for your replacement. Be sure to include a line about sending bulk emails. That way, anyone who applies for the job has a reasonable warning that they will be asked to spam.

TGI says moo