As Apple’s DVD Studio Pro software has an extensive user base, there are a great number of publicly available learning resources: books, CD-ROM’s, and websites hosting articles and user forums/discussions.

Books:

I recommend learning primarily via hands-on time with DVD Studio Pro combined with a clearly written, well-organized book. Books continue to have advantages in terms of clarity and organisation of information and ease and quick access to information (retrieval). They also continue to be handy reference material.

Of all the relevant books I suggest getting your hands on "DVD Studio Pro 3 for Mac OS X (Visual QuickPro Guide)" by Martin Sitter. Second choice is "Apple Pro Training Series: DVD Studio Pro 4" by Martin Sitter and Adrian Ramseier. DVD Studio Pro 4 is the most recent version of the software and is the version we have at Video In. It differs from version 3 only in that it adds a few advanced features. The latter book makes somewhat false claims of revision for version 4 as it does not include information about these new features. So, though the former book is for version 3 it is the better book and is relevent for version 4. For those interrested in learning the art of designing DVD menus there is "Designing DVD Menus: How To Create Professional-Looking DVDs". This book doesn't specifically teach us to author DVDs using particular software. Instead, this book is all about how to create professional-looking DVD by understanding the artistic side of authoring. These books are available through major resellers like Chapters.

Note that as of June 2011, DVD Studio Pro was officially discontinued, in favor of Final Cut Pro X.

Web Resources:

After that, I recommend additional learning via web resources. What they lack in clear organization and ease of information retrieval, they make up for in terms of providing up-to-date, interactive and shared, and vast information.

The best in my opinion is Ken Stone’s discussion and articles site.

DVD Studio Pro forum within the the support area of the Apple web site and the Creative Cow DVD Studio Pro forum both emphasize troubleshooting hardware and software issues/difficulties.

The LA FCP User Group has some tutorials and forums on DVD Studio Pro.

This resource is geared toward tutorial training is: rippletraining.com

Finally, for those that want to make a basic, menu-less DVD, I've created an article here.