Now that you're digging into ZBrush, these websites are worth a visit:
http://www.pixologic.com. As the developers of ZBrush, this site features many customer stories, tutorials, and most interestingly the turntable gallery, where you can rotate freely around ZBrush models from others.
http://www.ZBrushcentral.com. The main forum with answers for all ZBrush-related questions and a nice "top-row-gallery".
http://www.ZBrush.info. This is a wiki, hosted by pixologic, containing the online documentation for ZBrush.