To me, CBI or "learning a language through content" is a generalization of the common English teaching idea of communicative information gaps that need to be bridged in speaking activities.
Nowadays, I like to stay away from the mechanical "information" gap activity, transforming it into more of a "meaning" gap activity where the information gap comes from student projects or writing activities. My favorite, the marketing plan, where stundents design a Product, Pricing and Promotion for the product, and distribution (Place), which are called the 3 P's in marketing, has several opportunities for information or meaning gap exchange of information or roleplaying, marketing research via surveys and focus group sessions being two instances with opportunities for question formulation.
The hostility towards TESOL and the communicative approach shown by some more experienced teachers first struck me as unusual. One even called TESOL the "Hello, How are you?, I love you!" school of education. I now realize that the mainstream English teaching community (i.e. "TESOL") is, in fact, rather insulated, often resistant to outside intellectual influence and often unable to connect to broader-based educational research.
Studying higher-order ideas like CBI can help us do our lower level day to day work such as lesson planning more creatively and efficiently.
This introductory chapter from a recent book is a good introduction and overview of the idea of CBI (Content Based Instruction), learning a language by learning something else besides the language, using the language, albeit in simplified forms at first. Rather an ambitious task, wouldn't you say?
Table 1 in this book outlines the differences in applying CBI to novice and more advanced learners. An outline syllabus for novice learners is also given.
The table of "Kumar's Macro-Strategies" also provide a nice set of guidelines.
The bibliography is also very up-to-date.