It doesn't work for me :-(
I tried to create the symbolic link as suggested above but the plugin is still not found under about:plugins.
Then dpkg -S /usr/lib/squeak/3.7-7/npsqueak.so shows that its in the squeak-vm package,
and dpkg -L squeak-vm shows that shows that there is a script
/usr/lib/squeak/npsqueakregister I ran it and it just created yet another link:
>> create symbolic link `/usr/lib/mozilla/plugins/npsqueak.so' to `/usr/lib/squeak/3.7-7/npsqueak.so
which I suppose already existed when I installed squeak-vm.
Google found this post:
From here there is a link: http://www.impara.de/~jens/ubuntu/
but it no longer exists. I tried the wayback machine to retrieve an old copy:
http://www.archive.org/index.php but I guess it only archives text pages.
I am running edubuntu 7.10 and firefox 18.104.22.168