things to look at

http://www.3dtotal.com/index_tutorial.php?catDisplay=8&roPos=1&search=&p=1&sort=date&order=1&detailsoff=

http://naldzgraphics.net/tutorials/33-astounding-zbrush-tutorials-you-should-learn/

http://cg.tutsplus.com/articles/web-roundups/tutorial-roundup-82-earth-shattering-zbrush-tutorials/