I read men's health as well... also I go back and re-read all my college textbooks, as well as see if any have be updated and exchange those...
Also at my work I have access to ptonthenet.com and soon NASM's version of it... WebMD... Other fitnes forums, etc...
Talk with fellow trainers, we have weekly meetings discussing things...
LIBRARY! talk about a great source, but becareful, they do have some bad ones in there...