I am very, very tired of sending out variations on these emails. At least they're already written, and I don't have to try to write them from scratch each time. Option #1 is for the first-time offenders:

Dear [you]:

I've just received [number of] emails in quick succession that appear to be virus-generated emails from you. They look like emails generated by the Klez virus. The emails match viral patterns, include random images from my site, and are addressed to email addresses that are only available in the 'skin your website' tutorial that's available on my site (domesticat.net).

I checked your site, and you've recently posted that you plan on skinning your site, which probably means you've read the tutorial. The Klez virus (among others) scans files contained on your computer (including common web page extensions) and fires emails out to the email addresses it finds on the page.