Educational software

Good introduction article about educational software on the Linux desktop.
Some essential links from it:
The KDE Education Project

Schoolforge.net : To find Linux software check under Education Software on the left side of the page and select the GNU/Linux operating system at the top of the list.

Tux4Kids

and a link to a pdf file
Kids's Software for Linux

What this article leaves out of its focus is the incredible amount of cross platform educational pages on the web. Many use Java, youtube or flash content. I would like to mention the khanacademy.org site as a great example of youtube based content.
JClic as an example as community driven java software.