It is possible to install the free recent version of Ubuntu Linux,8.04 Hardy Heron on the Clamshell iBook. The PowerPC Desktop version needs at least 256MB RAM, i've installed it without problems on a 300MHZ Clamshell. This LTS (long time support- 3 years) version comes as a Live CD, that means that you can test it before you install it on your harddisk.