First of all, be aware that these probably won't work well on any operating system that isn't Windows 95, Windows 98, or Windows ME. On my modern machine running Windows XP, they do run... they just suffer from numerous glitches.
If you'd like to try running these anyways, what you'll need to do is download the ZIP file for the creation you'd like to view/hear, open the ZIP file (if you don't already have a program on your computer that can do this, get 7-zip), and extract all its files to some folder on your computer - preferably a newly-created empty folder, so that if you don't want these any more, you can simply delete the folder. Once all the files are extracted, open the EXE file to check out the SimTunes-y-ness.
If you'd like more information on SimTunes itself, see the Wikipedia article.
If you like the idea of animated music, I recommend that you check out some much more professionally-done stuff created by Wayne Lytle and his friends: Animusic.