I read the article that Professor Bud posted on the BIT course website and found it's useful even though it's only a brief introduction to XSLT.
It talks about XSLT's advantages over the old languages. It completely seperates content from design. Basically the content exists in XML and the structure exists in XSL. This fact better improves the workflow for website design since people can work on content and structure seperately and autonomously.
Then it gives us a few examples about how to do the stylesheet transformation. The best way to learn the language is to get your hand on it and actually write the scripts then just simply read it because there will always be some problems coming up along the process. And there are too many things we can do using XSLT, so I am still learning only a bit of it.