Since Rhapsody took from Mach, Netbsd, OpenBSD, and now is - i believe, identified as "Mac OS X Server". which is not a free download.
I do not see it available for download from the Apple ftp site, i will assume it is not something you can obtain legally without purchase.
if you want to try Apple code on your x86 platform, try Apple's Darwin.
Apple Darwin http://developer.apple.com/darwin/projects/darwin/
Gnu/Darwin http://www.gnu-darwin.org/
Open/Darwin http://www.opendarwin.org/
Darwin hardware compatibility list http://darwinunderground.com/hardware/
you were looking for "yellow-box" of the Rhapsody code. you best bet is try the Darwin, or maybe go for BeOS.
i run Beos 4.5.2 on a 200Mhz machine, and it handles very nicely, and has built in web server called PoorMan. You should still be able to download the BeOS 5 PE, but if you want to install it on a stand alone machine, you are best to purchase a BeOS 5 Pro Cd, if you can find one.
The nice thing with the BeOs 4.5 CD i purchased years ago is that it has code to run it on a x86 machine as well as a PPC.