[iBook] Sharing drive with iBook wirelessly

[vwmai]

Hi,

I have three computers at home. An iBook with an Airport Card, a G3 
iMac with a USB network adaptor and a G4 connected to a wireless router 
via ethernet. All three are running OSX 10.3.9.

The G4 has two hard drives one of which has nothing but mp3 files on 
it. I want to be able to share that drive over the wireless network 
with the other computers in the hope that I can point each machines 
iTunes to the iTunes music folder on G4's drive. I've been hunting 
through "help" but can't find a way to share the drive in the G4. Most 
of the info I find is about using the drop box. I would also like to 
share file in the document folder and photos form the G4 to the other 
computers. What's the best way to do this?  Also what are the security 
issues involved?

Thanks
Chris