Here’s a nice post on how to thwart email harvesting. Most of the suggestions revolve around using images in place of text address, obfuscating addresses, using forms in place of text and links…you know the drill.
I take a more simplistic view – don’t post email address at all.
Email is turning into a pretty ineffective form of communication, if for no other reason than you transfer the value of the communication to the recipient (meaning they reply when they want to, if they even want to). The fact that email has such a low variable cost makes the proposition even more one sided.
How about picking up the phone instead?