This is a great collection of tutorials.
Whether you are clueless about drawing or an expert you will find something here to learn.
From Beginner to Expert
Styles : From Anime to Realistic
-Painting techniques for -> Photoshop + Painter +Open Canvas
-Open canvas video demos (Open canvas required to run)
-How to do Tags and textures for Sigs
-Tones for Comics (brushes and patterns incl)
-Markers (Prismacolors and Copic)
-Improve your Perspective and Anatomy
-Charts for skin tones