Stan Winston School are sharing a free Photoshop character design tutorial by Dan Luvisi.
CGschool - Arch-Vis Training in 3ds Max, Photoshop and V-Ray
CGschool provides world-class architectural visualization training in 3ds Max, V-Ray and Photoshop.
Ben Mauro - ZBrush for Environments
Ben Mauro has released a free 3D environment design tutorial using ZBrush, Keyshot and Photoshop.
Cyborg Design - Concept Art Production Techniques
Instructor Michael Pedro gives a detailed overview on concept art production techniques in ZBrush and Photoshop.