PCB home page: http://opencircuitdesign.com/pcb/
Q: Is there any relationship between the opencircuitdesign PCB and the [gEDA PCB] ?
A: Yes. They are both derived from the same source. However, I decided to try to rewrite some of the code to allow PCB to compile as a Tcl/Tk extension, the way all the other tools on opencircuitdesign are. This allows PCB to be driven by command line, and thus in batch mode. However, my code was never folded back into the other branch, and since then, the other branch has made changes to the file format that make the two versions somewhat incompatible. As far as I am aware, the gEDA version is still maintained by harry eaton (a friend of mine) at the Johns Hopkins Applied Physics Lab, and the latest distribution version is always available on sourceforge.