Highly professional, highly paid webmasters such as myself (cough) know that the spambots will find any exposed mailto: link in a webpage and take steps to avoid potential problems. I’ve had great success in these instances with a little javascript scrambler such as the one found here.
Jason over at EveryJoe.com has a post about using an image or url in place of an email address in your webpages, emails, tweets, etc. here:
YMMV!