BKchem is a free chemical drawing program written in Python originally developed on Linux. It was conceived and written by Beda Kosata.
There was a set of instructions for installing under MacOSX 10.2 but they involved installing a variety of other packages.
I thought it might be interesting to see if it installed under MacOSX 10.4.8
Download the latest prerelease http://bkchem.zirael.org/download/bkchem-0.12.0_pre1.tar.gz and expand.
Open the Terminal and navigate to the folder
sudo python setup.py install
You should be prompted for your password and the installer should proceed.
When finished to launch BKChem type
It is a little rough around the edges but good to see another free chemical drawing package.
You can add this to your bash profile to allow you to simply type bkchem in the terminal to launch it.
At the moment this installs in the system framework which might not be the best place.