I just happened across a list of educational magazines at Amazon, aimed at both kids and teachers. There are about 60+ magazines listed, and I found it nice to have them all in one place, from Scholastic to Ranger Rick to Highlights. My kids grandparents like to give subscriptions as gifts, so I'm glad to have so many to choose from.
The link is
http://www.amazon.com/exec/obidos/redirect?link_code=ur2&camp=1789&tag=albuquerqhome-20&creative=9325&path=tg/browse/-/638992/ref=br_bx_c_2_0but you have to click through many different pages to see them all. I'm not sure how the prices at Amazon compare with what you could get them for elsewhere.
Update: ok, for some reason this link isn't working. I'm trying to fix it and but so far no luck. In the meantime, you can click on See all 32 Product Categories at the top. Then Magazines, then Family & Parenting, and then Education at
http://www.amazon.com.