A new solar cell simulation program, wxAMPS, is presented in this work. The interface of wxAMPS is developed using a cross-platform library, wxWidgets, and the kernel is based on an updated version of the AMPS (Analysis of Microelectronic and Photonic Structures) code. wxAMPS incorporates two different tunneling models for better simulation of specific types of solar cells. Compared to the drift-diffusion model, the intra-band tunneling model provides more realistic characteristics for heterojunction solar cells. The other tunneling component is trap-assisted tunneling current, which plays an important role in tunneling recombination at junctions. To increase the convergence property of this model, a new algorithm that combines the Newton method and the Gummel method has been developed. The simulation results from different models are compared. A preliminary WIKI has also been set up, which provides a database of materials parameters for various kinds of solar cells to help the PV community share materials data and more easily implement simulations.