Miami and Samba on the Amiga
Give the PC, or Second Network card if your first one is used for Cable Modem / ADSL, an IP address of 192.168.0.1
Host Name Amiga
Give the Amiga an IP address of 192.168.0.2
Hostname Amiga1
Netmask 255.255.255.0
Install samba on the Amiga and config as per the docs.
In XP connect to network place //192.168.0.2/ALL
you can map it as a network Drive Z: for example
smbclient -l Amiga on the show the shares on the PC
smbclient -l Amiga1 shows the shares on the Amiga