Look in your bin\nt folder under the folder that you installed the Xilinx tools. At that location, you should find a command line executable
ngc2edif.exe
This is what I used to use to generate the edif netlist that I used for simulation.
For building the XC3000 series of parts, I think you need the old tool set. Contact Xilinx, I think if you explain the situation they will allow you to download a copy of the old tools. Please be aware that this may be the old XACT tool chain and it is quite different from ISE.