I think I posted my post in the wrong thread here:
when I intended it to be in this thread. I'll reproduce it here through the magic of copy-and-paste:
Ebay has this page on reading headers:
and it links to the spamcop page on header-reading for different email programs here:
IMHO, it would be a Good Thing to add the gmail header-reading instructions to that Spamcop page. I've already contacted haltabuse.org about the same thing missing at their page.