Either protocol will work but...XP no longer supports NetBEUI. It can be installed but I wouldn't bother because TCP/IP will work just as well in your situation. The XP network wizard works well sometimes, and sometimes it just won't work. You can set up the 98 computer manually.
Control Panel, Network, Configuration tab. You should have: Client for MS Networks, your network card, TCP/IP, and File & Print Sharing (if desired). On the Identification tab, give the computer a name & use the same Workgroup as the XP computer.
This info along with the link that TheOldMan346 gave earlier, should get you there. If you need anything more specific just post back.