Ooh, a tweak to make the snippet more elegant. I just learned a new javascript tidbit - escape(variable). No more need for %20 instead of spaces!
<!-- email link -->
<script language=javascript>
<!--
var username = "davidfromblogdom";
var hostname = "blogdom.org";
var subject = "Hello from Blogdom";
var linktext = "Click Here To Send Me Email";
document.write("<a href=" + "mail" + "to:" + username +
"@" + hostname + "?Subject=" + escape(subject) + ">" + linktext + "</a>")
//-->
</script>
<!-- email link -->
Digg It!
Bookmark it!