David Richardson has created a multiple-part tutorial for modeling a mech in ZBrush.
ZBrush 4R7 ZModeler
Michael Pavlovich has made this quick run through of the basic functionality of the new ZModeler brush in ZBrush 4R7.
Fibermesh Hair Tutorial
Yuri Alexander has posted a tutorial on creating and rendering Fibermesh hair.
Ben Mauro - Yukon Pit Crew: Part 1
Ben Mauro has posted a ZBrush video tutorial, focusing on the development of his Yukon Pit Crew project.