Only drivers for Win 98 Second Edition could work on XP. Every operating system runs several driver models, the only ones that are common to XP and 98SE is the WDM driver model. There is no common driver model with XP and 98 or 95 (but 98SE can use 98 and 95 drivers as well).
But WDM drivers may call functions that only exist on Win 2000/XP or 98SE/ME thus making the driver not compatable with the other one (or even use a new XP only function so not compat with 2000).
In short you need to suck it to see.
For older hardware look for (where the web page was last updated before XP's release)
Win 2000 drivers
Win 98 SE or Win ME drivers (if WDM drivers)
NT4 drivers.