Admittedly, I've never spent too much time looking into it, so I might be wrong (I actually kind of hope it), but it seems to me that getting hold of a tracker program is not an issue, but getting a hold of any useful samples is. Typically, it involves either spending money (which is fine, I guess, but maybe not if you really just want to appeal to your nostalgia) or painfully wading through online archives of single sound samples in the hope of eventually gathering enough to create your own sample bank. That's a cumbersome process though, that would take toooo long for someone who just wants to casually try out a tracker again.
In the olden days, and maybe that was just because the Amiga trackers I had came from less than official sources, always came with at least one substantial sample bank included. Probably not the greatest samples, but you got a decent amount of bass sounds, some drums (kicks, snares, hihats) and some lead instruments. Granted, there were also many garbage sounds that you could probably never use (I remember samples from Star Wars movies, etc...) but besides those, there were enough actual musical sounds/instruments that you could use to make your own songs.
Like I said above, maybe it's just that I'm not looking in the right places, and I really hope that I'm just doing it wrong. So if you know how where to get samples for any tracker program (like, a comprehensive mixed set, not just single samples and not just a bank of 1024 bass sounds or so), please post a link.