You will need to set the IPs for each machine and a network share on at least one.
Win98:
Start>Settings>Control Panel>Network. Select TCP/IP and click properties. Select the IP Address tab, select Specify an IP.... Enter an IP such as 192.168.0.2 and 192.168.0.3, subnet mask for both is 255.255.255.0). Hit OK on each window.
WinXP:
Start>Control Panel>Network Connection
Right click Local Area Conection and select properties. Select TCP/IP and click Properties. Select Use the following IP Address, enter an IP and subnet above (IPs must be different, subnet is the same). Hit OK on each window.
Network Shares
In order to send the files across at least one machine must have a network share. On the WinXP machine create a temp folder somewhere to put all the files. Right click and select Sharing, enable sharing, give it a name and allow network users to change files (write access).
Since I don’t use simple file sharing I can’t really give specific steps in this part, I have a general idea of what needs to be done.
Accessing the Share
On the Win98 machine: Start>Run and type \\compname or \\ipaddress of the Winxp machine, double click the share and drag or copy/paste the files/folders.