Hilaire,
I must have missed this one, but the image is
http://www.squeakland.org/installers/SqueakPluginImage-dev.zip
(don't forget to update code).
The "development image" above is configured so that school kids can use it as little hassle as possible, as in the other installers available at:
http://www.squeakland.org/plugin/download.html
-- Yoshiki