Hawaii has an extensive Philosophy for Children (P4C) program that connects with similar efforts in Japan: http://p4chawaii.org/

The Stanford Encyclopedia of Philosophy has a very informative entry on the history of the Philosophy for Children movement, which includes a link to other internet resources. And a Google search for “philosophy for children” turns up more results than you’ll have time to sort through.

http://plato.stanford.edu/entries/children/

As a personal aside, I’m planning to help a group of parents who are homeschooling their children develop some philosophy exercises for their elementary-school-aged children. If anyone has experience doing this, please contact me via e-mail (contact information available on my website).

I teach a similar class at the University of North Carolina at Chapel Hill. In the fall semester, my students work with high school students competing in the local High School Ethics Bowl tournament; in the spring semester, we learn how to lead philosophy discussions in a k-5 setting. Beyond that, UNC grad students, undergrads, and faculty have been involved in outreach for years, in schools, retirement communities, a community college GED program, and a juvenile detention center. http://philosophy.unc.edu/outreach/

One suggestion and two follow-ups:

1. For young kids, Thich Nhat Hanh’s ‘Is Nothing Something?’ is a terrific book for starting philosophical conversations (yeah, some of it’s a little out there, but I’ve had some great chats with our kids starting with that book): http://www.amazon.com/Nothing-Something-Questions-Friendship-Everything/dp/1937006654/

2. Seconding Kimberly’s comment: every graduate student who is passionate about teaching should think about applying to teach a CTY summer course. I taught existentialism to 9th-10th graders one summer, and it was one of the most profound teaching experiences of my life.

3. I’ve recently gotten more involved with Wi-Phi, the project Gaurav describes. It’s a good resource. A lot of the videos (not all) are easily accessible to kids — my 10-year-old son has enjoyed several. Homeschoolers and people interested in incorporating philosophy into middle- and high-school curricula should check it out. The content is all free, licensed under Creative Commons, etc.

I teach a course like this at Cal State Northridge, using many chapters from Wartenberg’s book. It includes a fieldwork component in which the students must lead a philosophical discussion with an elementary school class. It is part of a special teacher training degree we have at CSUN. The syllabus is available on my academia.edu page:
https://www.academia.edu/8157797/LRS_250_Reason_Belief_and_Education

I’ve also recently found some philosophy for children apps, in the process of testing them out. You can google “Tinker thinkers” and “Sophia the Wise” to find them.

I did the M.A.T. in the P4C program back in the 80’s when the Masters program first started. Like all new programs, and especially those with an interdisciplinary focus, it was viewed with deep suspicion by those unfamiliar with it. I am so happy to see how much it has grown and how many departments now engage with it–especially as outreach in their communities. I know that Creighton University also has a very developed philosophy for children program. We are hoping to start something at Texas A&M.

The University of Oregon Department of Philosophy is into its third year offering “Teaching Children Philosophy” to undergraduates from philosophy, education studies and other disciplines. The course outreaches to more than a dozen third through fifth grade classrooms in the Eugene, Oregon public schools. There are two aspects that the U.O. outreach has developed to build upon Professor Wartenberg’s wonderful curriculum. First, most of the prompts for discussion come from original two-minute plays written by the course instructor in collaboration with his undergraduate students. These plays are performed by the children themselves just before each discussion, and they purposefully bring up philosophical issues that remain unresolved and act as catalysts for engaging talk among the children. Second, the classroom teachers are active participants in each circle discussion. They also write personal written responses –as do the university undergraduates–in the children’s philosophical journals, and they receive a toolkit of facilitating techniques that they can use in leading critical thinking discussions in other areas of their curriculum. This helps to create a strong relationship between classroom teachers and the university program.