Hit up a bookstore and grab one of the little postcards that come in the magazines you're interested in. Personally, I like dealing directly with the publications as opposed to third party sites that want to put you on every mailing list under the sun just so you can save a buck or two. I don't know about you, but I get enough junk mail as it is.
Alternately, you could look go to each publication's site to get a subscription. A google search should turn up a pretty good selection to choose from. Maybe about.com.
GLTY