You are going to need to set up a streaming server. Using Win98 is going to be the hurdle I think. Ugh.
I just checked, and the free Darwin Streaming server, which could deliver Quicktime or MP4 to your audience needs at least Win 2k.
What kind of bandwidth are you dealing with? Streaming audio is fairly demanding, and video is much more so.
I would check to see if you can get a Windows Media streaming server for free, but I think its not cheap. And it's WMP, which isn't the best, but is probably supported by the most home users.
Have you thought about just doing an audio stream? That might be easier to do, and it would just be a streamed MP3, which tons of programs can play. It's also a lot less bandwidth-hungry.