Most of the frontends available here may work, but they expect to find WMP9 or higher amongst other funny things, usually not available in a default win98se install. Not that these things are really usefull, but most of them were developped on a winxp/2k machine, and their authors tend to forget win98se is a real 32bit system ( just my rant , I know what can't be done on win98se, don't aim me with a flame thrower, I've mine ready, muhahahaha. lol ).
Besides, the real problem with win98se are GPS-routing apps. Some work just fine with Win98SE, but the most intersting ones don't. (insert my previous rant here too, upgrade it to "Rant Mk II" cuz' these apps aren't free.... Curse y'all, lazzy coders... bleh )
Currently I use mapstore (europe only) for GPS, and my own frontend, written in delphi on a win98se machine, only using WMP 6.4.07.112. for audio and videocapx for Rearcam and divx playback.