This instruction describes how to install Debian Squeeze on an iBook with a G3 PPC CPU. It is the way that worked for me and it might be usefull for others who want to bring back some live to a nice little machine.
1. Shrinking the Mac OS partition
2. Installing Debian Squeeze
3. Configuring Debian Squeeze
3.1 Right-click by Ctrl+click
3.2 Function keys and eject key
3.4 Keyboard mappings
3.6 Power management