The online modules I wrote about before contain links to another very useful set of documents that provide an overview and introduction to Corpus Linguistics from the University of Birmingham. They focus on how researchers in the Humanities can benefit from Corpus Linguistics. These documents are very clear and are a relatively short but sweet introduction to the field/methods.
I’m in the process of tracking down several of these sorts of training/tutorial/study materials. When I have a critical mass I will be adding a new page of study links.