Idnaf.Bode.Plot is a free and opensource software to draw Bode plot in which very important in many aspects of engineering. The software is available here.
In the zip file there are several folders which show you the sourcecode directory, the binary and screenshoots of the program. The “jar” is compiled using JDK 1.5, the code was edited using Netbeans 4.5 Beta. Enjoy it.