This post collects a few links to WGCNA-related material posted elsewhere on the web.
First and foremost, the WGCNA page maintained by me (PL) is the place to go for WGCNA downloads, the original set of tutorials and an FAQ.
Steve Horvath wrote a comprehensive book on weighted network analysis called, appropriately,
Weighted Network Analysis: Applications in Genomics and Systems Biology. It is available as an e-book from Springer as well as a regular paper book from Amazon. If you are affiliated with a university, your library may have an electronic subscription to Springer and you may be able to download the book without having to pay.
Several recorded lectures from various network analysis courses are available on youtube:
A full playlist of videos from the 2015 Short Course on Network Analysis is also available.
The co-expression network home page maintained by Steve Horvath and his lab contains links to many of journal papers that introduced aspects of WGCNA and used it in a variety of applications.