This method could be used with a DB25 connector, a DB36, or any other angled PCB mount socket. My example uses a socket and cable with a 36 pin Centronics connector, as found on many old printers, because that's the kind of cable and socket I had from a printer I took apart. If you want DB25 like a standard computer parallel port, it's pretty easy to find an old motherboard with one of those sockets that can be used in exactly the same way.
1 DB25, Centronix 36pin or other PCB mount socket that you want to adapt to a breadboard.
1 40 pin IC socket, preferably the kind with flat tabs, though the machined pin kind may work
Zip ties (optional)
Needle nose pliers/tweezers
Solder sucker or desoldering iron (if your plug is currently attached to a board)
Step 1: Desolder and Crack the Socket
So, getting on to that, take a pair of pliers and crack up the plastic on the back of the connector. Since it comes to an angle behind the connector it breaks away pretty cleanly. If you want to be really neat about it you can file off the rough edges left where you broke off the plastic surrounding the pins.
Step 2: Plug the Pins Into the IC Socket
Step 3: Solder the Pins Into the Socket
After all the pins are soldered gently bend down the plug and bring the other row of pins near the socket. Repeat step two for this side and then solder in the same manner.
Step 4: Plug It Into Your Breadboard
On one of my breadboards I locked an adapter like this one down by drilling holes through the breadboard in the grove in the middle where there aren't any holes. just off each end of the adapter using a 3/16 drill bit. Then I put a zip tie across the top of the IC socket but under the pins of the connector for the printer cable and through the holes in the breadboard. The last picture shows the one that zip tied to the board. It's given me a good solid connection for prototyping CNC drivers.