Ben Mauro has posted a ZBrush video tutorial, focusing on the development of his Yukon Pit Crew project.
Art for Games - Custom Alphas Tutorial
Art for Games have launched their game art education site, along with a new tutorial on custom alphas in ZBrush.
ZBrush SIGGRAPH 2013 Recap
Here is a massive recap of ZBrush's presentations from Siggraph 2013.