Bear in mind that if you extract them on Windows you will lose resource
fork*, which contains sounds, icons and externals.
That being said, I've had _a lot_ of success with a tool called the
Unarchiver. Not only can it extract .sit, but also .hqx, .sea, .bin and
most other archive formats. It really does do everything you could ever
need. (It is so versatile I use it as part of the backend for HyperCard
Online, because it will be able to extract almost any format that is
uploaded).
Perhaps the only downside for the Unarchiver is that it is command-line
only. I don't find that much of an issue (in some cases it makes thing much
easier). Simply head to
https://theunarchiver.com/command-line<
https://theunarchiver.com/command-line>; and download the Zip under the
"Windows" heading. You'll get two tools, unar (which actually unarchives
stuff) and lsar (which lists the contents of archives without actually
extracting anything).
For example, *unar myZip.zip* will unarchive the contents of the zipped
folder myZip.zip.
*(In fact, the unarchiver is able to extract the resource forks. They're
not particularly useful, because nothing can open them, but it's nice to
know that feature is there)
Last thing:
I have unar/lsar on my computer right now. If all the above seems too
complex, feel free to email me the .sit and I'll extract it for you.
Andrew