VSTAR (Versatile Software for Transfer of Atmospheric Radiation) is a new atmospheric radiative transfer software package developed at the Australian Centre for Astrobiology. It is designed to be sufficiently general to be applied to the atmospheres of the Earth, other solar-system planets, and extrasolar planets. VSTAR solves the radiative transfer problem in a plane-parallel atmosphere by combining a line-by-line treatment of the molecular absorption with a full multiple-scattering solution of the radiative transfer equation incorporating Rayleigh scattering and scattering from clouds and aerosols. VSTAR is highly portable and compiles under a range of Fortran compilers including the freely available g77 compiler. Development of VSTAR began in 2002 with most of the current code being completed in 2005. It is thus a modern system designed to fully exploit the high performance of modern CPUs and the large memory capacities now available.