actually, most new harware and most software from today wont even work in win 98.why would u want to use win 98? as jobeard said, there is no support or updates even for the base win xp, only if u already have sp1 installed, let alone 98.
I'd fire up gparted from a live cd, and delete all the partitions. Then startup with a 98 floppy and run fdisk. Set up your partition that way, then I forget whether you actually need to format the drive or whether you can begin the 98 setup and have it recognise the partition and format.
You actually may not even have to manually use fdisk, you might be able to just run from the cd and have it ask to set up partitions. Its been about 8 years since I've installed 98.
I have an old Dell PC using Windows 98SE that I don't use much anymore. I believe existing security updates are still available through Windows Update, just not any new ones of course.