None.
1). Microsoft stopped supporting Win98 something like 7-8 years ago.
2). Todays hardware is too fast for Win98, even the technology 8 years ago was too fast for it.
Speaking from personal experience, I found that Win98 was unstable on DDR ram or newer. I've currently running my Win98 on a Pentium 3 with SD ram, an Athlon (original, not XP or newer) should also work fine. I suggest trawling eBay.
On another note, I have tried to run it on Virtual PC without success.