I agree that emphasis on critical thinking and analytical skills should be an essential element of any programme but from my admittedly limited experience the IB approach does not go as far in this direction as one might desire. Caveats; 1) the IB ToK element is better than the nothing most curricula I am familiar with have and shows the good intentions of those setting up the course, so this is not a 'it's no good' but a 'could do better' comment and 2) not having gone to a school which taught IB, my experience has been limited to the handful of students I have discussed this programme with or offered ad hoc tutoring to in connection to the ToK element.
From what I can see, though the actual process of what is taught in classrooms and how it is taught may differ, in terms of what students seem to be producing at the end of the course the ToK element amounts to little more than Epistemology 101 where rather than being, as you put it, about 'how to think, not what to think' it is instead about 'what to think', just at a meta- level; 'what to think about thinking'. If you wish to stimulate critical thinking I'm inclined to think intensive classroom based discussion of comparative analysis of arguments and source handling is superior to teaching the difference between the a priori and the a posteriori, or raising the possibility of absolute scepticism. I say this with no prejudice against epistemology, as a philosophy postgraduate student some of my best friends are epistemologists, but if the question is 'what would be the best way to structure a curriculum so as to raise a generation of genuinely critical thinkers' I don't believe the answer is teaching them about Plato's myth of the cave or the disputes between empiricism and rationalism. Perhaps such basic distinctions require some coverage, if only to avoid obvious howlers such as failing to recognise the use/mention distinction or the like, but for real critical thought it would seem better if the curriculum was structured so as to emphasise critical thought in all subjects in the form of subject-specific problem based critical analysis.
Public schools (and arguably private schools as well; I wouldn't know) teach students what to think, not how to think.
On LessWrong, this insight is so trivial not to bear repeating. Unfortunately, I think many people have adopted it as an immutable fact about the world that will be corrected post-Singularity, rather than a totally unacceptable state of affairs which we should be doing something about now. The consensus seems to be that a class teaching the basic principles of thinking would be a huge step towards raising the sanity waterline, but that it will never happen. Well, my school has one. It's called Theory of Knowledge, and it's offered at 2,307 schools worldwide as part of the IB Diploma Program.
The IB Diploma, for those of you who haven't heard of it, is a internationally recognized high school program. It requires students to pass tests in 6 subject areas, jump through a number of other hoops, and take an additional class called Theory of Knowledge.
For the record, I'm not convinced the IB Diploma Program is a good thing. It doesn't really solve any of the problems with public schools, it shares the frustrating focus on standardized testing and password-guessing instead of real learning, etc. But I think Theory of Knowledge is a huge opportunity to spread the ideas of rationality.
What kinds of people sign up for the IB Diploma? It is considered more rigorous than A-levels in Britain, and dramatically more rigorous than standard classes in the United States (I would consider it approximately equal to taking 5 or 6 AP classes a year). Most kids engaged in this program are intelligent, motivated and interested in the world around them. They seem, (through my informal survey method of talking to lots of them) to have a higher click factor than average.
The problem is that currently, Theory of Knowledge is a waste of time. There isn't much in the way of standards for a curriculum, and in the entire last semester we covered less content than I learn from any given top-level LessWrong post. We debated the nature of truth for 4 months; most people do not come up with interesting answers to this on their own initiative, so the conversation went in circles around "There's no such thing as truth!" "Now, that's just stupid." the whole time. When I mention LessWrong to my friends, I generally explain it as "What ToK would be like, if ToK was actually good."
At my school, we regularly have speakers come in and discuss various topics during ToK, mostly because the regular instructor doesn't have any idea what to say. The only qualifications seem to be a pulse and some knowledge of English (we've had presenters who aren't fluent). If LessWrong posters wanted to call up the IB school nearest you and offer to present on rationality, I'm almost certain people would agree. This seems like a good opportunity to practice speaking/presenting in a low-stakes situation, and a great way to expose smart, motivated kids to rationality.
I think a good presentation would focus on the meaning of evidence, what we mean by "rationality", and making beliefs pay rent, all topics we've touched on without saying anything meaningful. We've also discussed Popper's falsificationism, and about half your audience will already be familiar with Bayes' theorem through statistics classes but not as a model of inductive reasoning in general.
If you'd be interested in this but don't know where to start in terms of preparing a presentation, Liron's presentation "You Are A Brain" seems like a good place to start. Designing a presentation along these lines might also be a good activity for a meetup group.