I read about WebCorp in Dubravac's chapter 3, and it is definitely worth checking out. You search for words or phrases, and the website pulls up concordance lines (key word(s) in context) for the words as they are found on webpages. The search results also include links to these websites.
This 50 page article, which was referenced in DuBravac (2013), provides a very thorough overview of corpus linguistics and concordancing for language classes. There is a ton of very relevant and practical information here! This link defaults to a section providing sample classroom corpus activities. My favorite uses a corpus for Tennyson's poem Mariana as a way to engage in literary analysis!
Corpus Linguistics, which is dealt with by Tony McEnery & Andrew Wilson inModule 3.4. Section 2.2 of this module includes a brief introduction to corpus linguistics.