Chris K writes (excerpted):

I'm teaching myself and home educating my three young daughters at the same time. Just a little bit every day (excepting Sunday which is entirely reserved for pancakes and not inter-computery-things) . Thank you for providing the opportunity for me to introduce the subject of computer programming in a fun way.
Anyhow, we hit a snag early on that does not seem to get a mention on the publishers site or your blog. When instructed to search for IDLE on the Ubuntu software centre nothing of relevance was listed. I had one of the girls do it and she was very disappointed...
...I've done some homework and followed instructions on installing idle3, which worked. So we are all set to go today.

I don't know how useful this feedback is to you but this is an opportunity to express my appreciation for all your hard work and skill, so I'm taking it.

The next re-print of Python for Kids will include updated instructions for installing IDLE3 on Ubuntu - which obviously doesn't help anyone reading the current print of the book. My steps are pretty similar to the link you've referenced:

snippet from the book

Thanks for the email - it's a good prompting to put something on my site, which others in the same position might come across.