E.g. [link|http://cgi.ebay.com/COMPAQ-LTE-150-MHZ-LAPTOP-WINDOWS-98-CD-AND-LICENSE_W0QQitemZ270059372148QQihZ017QQcategoryZ140082QQssPageNameZWDVWQQrdZ1QQcmdZViewItem|This] Compaq laptop has Win98 installed and comes with the CD and license. You might find something similar for your HP.
Maybe a fresh, legit, CD of Win98 for [link|http://cgi.ebay.com/Brand-new-Sealed-windows-98-and-CD-Key-plus-manual_W0QQitemZ280054344239QQihZ018QQcategoryZ41884QQrdZ1QQcmdZViewItem|$0.01] would be worthwhile. Copies of WinME for < $20 are available too. I dunno if they has all the drivers you need, though.
I suspect you'll have better luck simply finding another machine with it already installed, if you're determined to keep running it. Even though you've had good luck with it, Win98 is really a dead end.
Or, just say the word if you'd like another Linux CD care package. :-)
Cheers,
Scott.