At Michigan State University, we catalog zines more or less exactly like we catalog other more conventional publications. We'll catalog them as books or serials - determining which method to use on a case-by-case basis. I do most of the zine cataloging myself. I catalog them in MARC using AACR2 (for the time being, anyway - RDA is right around the corner). So they're just as "easy" as other materials, in a sense. However, I do avail myself of certain non-required treatments, like adding summary notes to enhance keyword access and genre headings to aid in collocation of zines based on genre. I find these treatments important to circumvent some of the value-laden language of controlled vocabulary subject terms (for example, making sure that someone searching for queer zines can find them, despite the fact that that's not language that would occur in Library of Congress Subject Headings).
For other libraries, considerations such as time and the availability of copy cataloging may be a factor, so they might consider cataloging zines as a collection, rather than item by item. Still others may do item by item cataloging, but forego MARC and AACR2 to use a homegrown database.
Jenna Freedman at Barnard College has worked with zines, including cataloging, for several years. This chapter of hers is helpful for thinking about zine cataloging:
- Freedman, Jenna . “AACR2-bendable but not flexible: cataloging zines at Barnard College.” Radical Cataloging: Essays at the Front. Ed. K.R. Roberto. Jefferson, NC: McFarland & Co, 2008.