Software can be made to run as though under Win95/98 in XP and drivers are for hardware - or are you referring to scanner/priter/etc?
If you are looking to add a printer, say, that ran under Win95 and have drivers for this I would personally install the hardware and the system will advise whether updated drivers are needed. When I moved from 95 to XP I was able to use all my hardware as XP has a list of Plug&play drivers of it's own. I would guess that if I had a printer made by XYZ company and this could not be found, the updated driver should be available on the manufacturer's website. Of course, if one is not available then the hardware is completely incompatible and requires updating anyhow.
I also had a few older programs - all of which I have changed the compatability [right click on icon, select compatability and tick 'run this program in compatability mode, then choose the OS it worked under from the dropdown menu].
If I have misunderstood, my apologies. Could you explain further?