No Longer Active. These must be downloaded
https://cgcookie.com/archive/introduction-zbrush/ Archived
https://cgcookie.com/profile/cyruse4/ Archived
Active Tutorial
https://design.tutsplus.com/courses/creature-design-in-adobe-photoshop
https://design.tutsplus.com/courses/digital-inking-in-adobe-photoshop
http://www.digitaltutors.com/tutorial/1275-Integrating-3D-Renders-into-2D-Art-in-Photoshop
http://www.digitaltutors.com/tutorial/1161-Creating-a-Prehistoric-Creature-Bust-in-ZBrush-and-Photoshop
http://www.digitaltutors.com/tutorial/577-Illustrating-a-Vintage-Horror-Film-Poster-in-Photoshop-and-ZBrush