Uses for a G4 Powerbook
Assuming you have the Airport (wifi) card installed:
- plug in a USB printer and you have a wireless print server (under sharing in system preferences)
- plug in a USB modem and you have a wireless Internet server (under sharing in system preferences)
I do both on my 10 year old Pismo Powerbook running 10.4. You can also install VNC so you can remotely manage the laptop from another computer.