Be prepared to deal with lawyers. If someone violates your copyright, and you feel that some sort of redress is owed you, then it's up to you to sue them. If your work is appropriated by someone who makes a zine don't expect to get much. Shareright, like this document, where anyone can copy it as long as they allow anyone else to copy it from them. Because you can't copyright a title, you must trademark it.
Trademarks are different, sorta.
Register your trademark in California. It's trademark violation that has caused pain and suffering for zine publishers. After trademark violation, the only thing you have to worry about is the morality cops busting down your door and sending you to jail like Peter Sotos or Mike Diana. Actually, ezines are the largest growing segment of zines right now, and the ezine FAQ has been written to answer you questions about them. Not wanting to keep this just on The WELL, I asked Ed Vielmetti how to go about creating an alt newsgroup.