Pixologic offers a comprehensive, informative and helpful website to support you with ZBrush. You will find a quite extensive section “Learn ZBrush”. In this section you will find detailed video tutorials for every skill level, from beginner to intermediate to advanced. There is a large selection of videos offering a variety of ZBrush lessons. You can view them in chronological order or just search for what interests you.
Pixologic also offers free ZBrush courses. You can take the basic course “Getting started” or choose from many other courses. The course selection includes: “Digital Sculpting & Modeling”, “Texturing”, “Posing & Animation“, “Rendering” and “Plug-ins”.
If for any reason you need more information, you can directly contact the ZBrush community where you can interact with other users, participate in group meetings or read the ZBrush blog for news and tutorials. If there are still questions, users can get help directly from the ZBrush support area.