How to setup a Multi-Platform Network?

[rockstar]

The following systems will be in the network:

2 iBooks @ 600MHZ G3 using MAC OS X
1 Compaq Laptop @ 900MHZ Duron using Redhat Linux/Windows 2000
1 Generic desktop @ 900MHZ Pentium III using Windows 2000 Server/LinuX
1 Powerbook G4 @ 550 MHZ using MAC OS X

Currently, the Generic desktop using Windows 2000/Linux serves as a file
server and Internet gateway. ALL MAC OS X users can access files from
the Generic desktop using either Windows or Linux and the Compaq laptop.

What we would like to accomplish: Using the Powerbook as the gateway
to the internet and allowing ALL non-MAC OS X users in the network to access files and folders the same manner the MAC OS X users are accessing the current Windows/Linux system. Can we accomplish this task using only the current resources in MAC OS X? Or, do we need a 3rd party software?

Please understand that ALL users in this network is new to MACINTOSH system. Any advise is greatly appreciated.


RockStar!