for XP to work with Win98 you need to use the WinXP Setup Disk's - you'll need 3 Blank disks and then run
cdrom:\i386\WinNT.exe
it'll put you through the setup by setup guide, becuase what you need to do is setup XP like WinNT rather than upgrading 98
Make sure you have a newly partitioned unformatted harddisk/partition. Now use C:\ as your Win98 drive and partition it in FAT32 ... and then install 98
once this is done and you've installed all the drivers so that it is in a useable state, insert the first disk and reboot the machine.
WinXP will now run through an NT like installation - it'll copy across all the basic setup files to the C:\ so make sure you have atleast 500mb free.
Then it'll ask you where you want to install XP, choose the un formatted hdd/partition and then choose what format you wish it to be FAT32/FAT64/NTFS
it'll piss about for about a while formating it, which for a FAT32 system will take around 1hr30min on a 40Gbyte.
Once the formatting is complete it'll copy across the temp files to that directory (yes very slow and wasteful way of doing this but nessary) and then ask you to reboot to continue the installation in a 32/64bit environment.
When you reboot you'll be given a familar option menu of Windows XP (Normal)
Windown 9x/Me
Windows XP (Safe Mode)
just leave the menu to boot up and you can change it later once in XP... it'll run through the installation pretty much if it was on a clean/complete install.
And only about 2/3hrs later you have both working
Installing WinNT/2000 as well oftenly is the tricky part hehee
Anata aru kowagaru no watashi! 