Hi Robert,
I haven’t taken their training, but as a general recommendation corelanc0d3r’s tutorials cover many different topics that would be useful as a preparation. Similarly, you can find some tutorials by FuzzySecurity, The Grey Corner, Security Shift and Open Security Training. And of course other great resources like phrack and PoC||GTFO.
Looking at the course syllabus and searching for the covered examples that are used during the training, you can find some tutorials and further explanations that deal with the same vulnerabilities online. For example, for “Module 3: ActFax (OSVDB 89944)” a tutorial is provided by Craig himself (assuming it is the same vulnerability that he discovered) as well as by others. The same applies to other examples covered such as “Mozilla Firefox (CVE-2011-2371)” (see here and here).
If you decide to take the course it would be great to see a review. 🙂