Any advice on stopping potentially professionally damaging internet/usenet "attack?"

I have been subjected to a series of personal internet "attacks," and these attacks are directed towards damaging my personal and professional reputation.

The "attacks" are from an Evangelical Christian "minister" (believed to be fraudulent) who claims to be the Dean of "Georgia Bible School and Theological Seminary." I am not the first to land in his "crosshairs" ... his smears are prolific and widely posted on the internet/usenet groups.

The "attacks" typically take the form of "smears" regarding views on abortion, homosexuality, and misleading statements (or outright lies) regarding professional status and performance.

The "attacks" appear to be motivated by professional envy - I am a professional musician and he plays the same intrument - or quite possibly bigotry.

I am looking for any advice on how to leaglly stop these attacks, and if necessary, to seek damages.

Any advice would be appreciated.