There is a hack for iTunes to run on OS 8.6 but I don't remember where to find it. I would reccomend looking first for it here (by doing a search) and then next on versiontracker.com. I'm sure you'll find it.
i would recommend upgrading to os 9. if your computer cant handle os 9 then itunes is probably gonna run like trash. i would go check out soundjam mp, same developers made itunes and its a great piece of software.
unfortunately iTunes 1.0 lists as system requirements OS 9.0.4. So the only possible alternative is some sort of hack, personally I don't believe such a thing is possible.
there is a little hacky type program that will allow you to run it on OS 8.6... i know cuz i used to use it. I forget what it is called but if you search versiontracker im sure it is still listed. (just be sure to click the "Mac OS" button at the top
The 7100 can only run up to 9.1, which know one that i know has. I'm looking to use the 7100 as an mp3 jukebox, and since its an av model, I would set the resolution to 640x480 and use my tv as the display.
This means that you can run up to precisely iTunes 2.0.x on your machine. Forget about running or trying to install QT 6.2 or 6.3 on your machine to use AAC files on a 7100, either.