This was a bare-knuckle, how-does-XSLT-work kindof talk. I think I was looking for a gentler introduction. Something that would be more motivating. Working through examples, showing a problem, and how XSLT elegantly solves said problem. Basically, I think that this talk needs some presentation Aikido. The presenter, Evan Lenz, really seemed to know XSLT backwards and forwards. And he prepared a nice quiz, which was a great way to work through some of the complexities of XPath. In addition, it fostered some group collaboration, in that we broke down into teams of two in order to go through the questions. All he needed in his presentation was more of an emphasis on case studies, real-world examples, and stories. He was basically trying to teach XSLT in the course of this tutorial. Which, if I want to learn a new language, isn't typically how I go about things.
Some notes that I harvested from the presentation:

• Michael Kay's "XSLT Programmer's Reference", well-regarded text on XSLT.
• Eventually, the slides will be available here: http://xmlportfolio.com/oscon2005/.
• If XPath is about trees, XSLT is about lists. Populate arbitrary nodes from the source tree into lists. Iterate over those lists to produce result tree.

Languages:

• XSLT
• XPath - language for addressing parts of an XML document.
• XPath is part of XSLT is part of XSL

XSLT debugger (Xselerator is an example) is quite helpful in learning:

1. What does my XPath expression select?
2. And what substitutions are being made as a result?