In a nutshell,
You will need to configure a static IP address for each machine, like 192.168.0.1 & 192.168.0.2. Use Mandrake control center to configure the network adapter. In XP, click on the properties of the network adapter and select tcp/ip. Select use static IP.
For copying files there are several choices.
Use a FTP server on linux side and a FTP client on XP.
Use samba. The linux PC will show up in network neighborhood.
www.samba.org