Chemtool is a GTK+-based 2D chemical structure editor for X11. Drawings can be exported in XFig format for further annotation, or as Postscript files (using xfig's companion program transfig). A set of sample molecular structure drawings is included in the archive.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.