A primary factor in the success of the Internet has been its ability to support heterogeneous networks, equipment, operating systems and software. However, this diversity coupled with security concerns makes creation and management of Internet applications more complicated than traditional ones in a static and well-defined environment. Internet Programming envisages being able to harness the power of the Internet by sharing resources and information in a secure and efficient manner. In this paper we present the Mobile Computational Model - a model that can fully support the Internet Programming paradigm through mobile computations. Mobility, communication, and security are supported at the language level through constructs provided for the purpose, strong type-checking, and other safety-promoting devices. They are also explicitly addressed at the management and execution levels. Portability on heterogeneous systems, and efficient execution of computations are assured through the RISC virtual machine. A prototype implementation of the Mobile Computation System, including the Mobile Computation Language, the Mobile Computation Manager and the RISC virtual machine, provides a proof-of-concept for the model. Preliminary testing has yielded encouraging results leading us to the conclusion that our model is a viable approach for Internet Programming.