Andy Carvin writes about using Wikipedia productively for K-12 classes; both to help them learn to research and to help fact-check the encyclopedia. http://www.digitaldivide.net/blog/acarvin/view?PostID=4746

Carvin hearkens back to a '96-era discussion on the "WWWEdu" email list (now housed at yahoogroups : http://groups.yahoo.com/group/wwwedu/), in which they discussed setting up a "kidopedia" with St. Johns University. Kidopedia had many things in common with wikipedia: it had nomenclature issues; it began with a mailing list (restricted to eight-letter addresses?) named "kidpedia@sjuvm.edu"; and it was meant to be "an encyclopedia for and by the K-12 Internetters who will be multicultural and multilingual, as well as multimedia." (http://tinyurl.com/9bakq)

Here is mention of a related grant proposal, which might be relevant to Wikipedia grant efforts: http://www.evergreen.loyola.edu/~rcrews/sl/archives/95/jun95/0005.html

And our own project focused on kids, with a much narrower scope (which could still use your help): http://meta.wikimedia.org/wiki/Wikijunior