I installed a Ubuntu 8.10 last Friday for Grace. Actually, it is Edubuntu. That means install Ubuntu 8.10 desktop version on PC first. Than install Edubuntu add-on on it.
There is a lot of software for free. Free to install, free to use. For kids learning.
What about Ubuntu 9.04
I think it may have thousands of new features.
One I am interested is better performance on SSD.
My netbook has SSD driver with Windows XP. I want to install a Linux on it. So Ubuntu 9.04 is the best bet.