If you're like me, you are lost without the beloved Korn shell. Oddly enough, it's not included with OSX (of course, that statement most likely points out my lack of knowledge in BSD).
Anyway, I found 'pdksh', and was able to successfully compile it on my OSX 10.0.1 system.
I had to tweak a few things, such as add a .profile to my home directory. You also need to use the Terminal Preferences to change the shell of the shell (?) to /usr/local/bin/ksh. I also updated /etc/shells, although I'm unsure whether or not that was needed.
Try this link - http://web.cs.mun.ca/~michael/pdksh/ - for more information.
Of course, make sure you are root during the install process.
I also might add that I haven't done any extensive testing of the ksh, but so far it behaves as I expected, and also runs various shell scripts I had written on Solaris 2.x.
Good luck!
Frank
Mac OS X Hints
http://hints.macworld.com/article.php?story=20010417162019608