Just stumbled on this:
What Google Leaves Out
http://www.microdocs-news.info/newsGoogle/2003/05/10.html
Regarding email mangling, here's a javascript i've used:
var sUsername="user";
var sDomain="example.org";
var sSeparator="@";
var concat=sUsername+sSeparator+sDomain;
document.write(concat.link("mailto:"+concat));
Maybe a jpeg is more useful, but I don't get spam :) (but I recently received a couple of scam messages to the address I use solely at openacs.org, maybe it was harvested by a human)