I’ve put all of my "Introduction to Zbrush 3" training online for FREE (the best part) as a gift to the Zbrush community. I used Vimeo to host them, meaning they are in full resolution HD, available 24/7. I recommend Vimeo to anyone wanting to host tutorials or demo reels, the quality is amazing. I believe it has a lot of good information inside that will help anyone that is looking to learn or improve their skills in Zbrush. Hopefully somebody can find some use out of them before they may become irrelevant due to the new versions. 
I’m personally really excited about Zbrush 3.5..

Chapter list:

Chapter 1 -  Introduction and Hello           3 Minutes

Chapter 2 -  Explanation of Pixols            6 Minutes

Chapter 3 -  Interface                                  40 Mintues
Chapter 4 -  Sculpting                               45 Minutes
Chapter 5 -  Masking and Selection          26 Minutes
Chapter 6 -  Advanced Sculpting              38 Minutes
Chapter 7 -  Zspheres                               32 Minutes
Chapter 8 -  Subtools                                20 Minutes
Chapter 9 -  Transpose                            12 Minutes
Chapter 10 – Texturing Techniques           36 Minutes
Chapter 11 – Matcapture                           14 Minutes
Chapter 12 – Retopology                           60 Minutes
Chapter 13 – Simple Displacements           16 Minutes
Chapter 14 – Illustration Techniques             10 Minutes

Click Here to go to the Zbrush 3 videos on 3dArtSpace.com.

Click Here to go to Vimeo for Zbrush 3 videos.  

For more up-to-date videos, see Gnomonology.com.