Beef Magazine - not show cattel related but has lots of info about breeding, raising, marketing, commerical cattle, and has lots of info about cattle in general
http://beefmagazine.com/
the American Simmental Association puts out a FREE magazine geared toward cattlemen, comerical producers and its got ads, peer reviewed articles, and lots of good info, including the Sire Summary... its called SimmTalk, i belive it comes out 2-3 times a year , heres the link to sign up for it
http://www.simmgene.com/
ASA also has an official publication called the "Register" , it is monthly deal, and i don't know what a subscription costs, but can be found at the same site the SimTalk is at.
Show Circuit is always good, espeically the editions with everyones fall sales, it allows you to look through and get some ideas of what cattle are out there to buy if you are looking for the next season's HF / Steer and its a good "john reader too"
http://www.theshowcircuit.com/
Livestock Plus - more focused on midwest area, i started getting this one and have really like it, has alot of smaller (and the big ones) breeders in it, so you can find so more variety of cattle from around Nebraska, Kansas, Iowa and Mizz.
JWW