sorry, I should have explained ....
The simplest way would be to link the two together using a crossover ethernet cable.
They are quite cheap, and easy to setup.
So, when you need to transfer files to/from computers,
just plug the crossover cable into both machines and
use nfs to 'mount' the exported part(s) of your linux filesystem on your ibook.
Once transferred you 'umount' (not a type) the share and then unplug the crossover.
ie. network filesharing 'as required'
you will need to examine (on your linux machine at least

):
/etc/exports
/etc/hosts
/etc/hosts.allow
Try typing 'apropos nfs' on your linux machine to improve your understanding.
This link might help too:
http://nfs.sourceforge.net/nfs-howto/server.html
A google for 'network file system nfs howto' (or similar) will give you an
idea of the issues involved.
Good luck