In regards to ibill, they do have a policy that their customers can't spam. I remember this from 3+ years ago when we first signed up, our rep was advising on how to do this (we never spammed though). While it's against their policy, sounds like they don't enforce it.
Don't bother with the out-out link, it'd probably bring you more spam, not less.
An article I wrote here tells you how to track down the offending site -
http://ynotnews.ynotmasters.com/issu...402/page5.html
but note that the only link you need to look at is the one they want you to click on. The email "from" info is bogus for sure, and the opt-out is questionable at best.