I frequently participate (and am mildy obsessed with) www.bookcrossing.com. It's a site where you can register and track where your books go, make journal entries about what you thought of the books, trade books, etc. One of the things you can do on the site is start or participate in a "bookbox." The idea of a bookbox is that you send out a box of books to the first in a list of participants. They look through it, take out a few books, go through their old books and put the same number back that they took from the box.
Unfortunately, you can't trade zines on bookcrossing because they aren't technically books and don't hold up well when mailed again and again or released into the wild. However, I love bookboxes so much that I'd really like to do something similar with zines.
I would put a certain number of zines in a box or big envelope and then gather a list of people who want to participate. I would send it off to the first person, they would take some zines, and then add the same number of zines from their collection. Then they would send a message to the next person in line to get their mailing address and send it off to them and so on.
At the end, the last person sends the box/envelope back to me.