We present the development of the graphical user interface of a conformal FDTD software package utilizing the Visual Basic programming language. We describe a complete interface, including the drawing of three-dimensional objects, the generation of non-uniform and conformal mesh, interfacing with AutoCad and GID, and data post-processing. The engine for the software package is based on a conformal FDTD algorithm, designed to handle general electromagnetic problems, including curved PEC and dielectric surfaces, without the use of "staircasing". To illustrate the versatility of the package, we present several representative simulation examples, viz., the modeling of a microwave stripline, a patch antenna, a triangular antenna, and the evaluation of the surface impedance of Earth. We also provide a comparison between the numerical results derived by using this package and other commercial software for a patch antenna.