This is the first time I have seen or heard of the Queensland based Media Culture.org, and their article on Blogging - Educational seems pretty good, with some interesting links out on the topic too.

From the article:
“…Will Richardson, one of the leading advocates of educational blogging and maintainer of Weblogg-ed, believes that more teachers and schools are beginning to experiment with the technology as a communicative tool for students and parents, a place to publish student work and “manage the information that members of the school community create” – it has also been seen as a cheap alternative to course management systems (Downes, 2004)…”