NeuronPM is a free client/server application that makes parameter maps for neural simulations written in NEURON (Hines & Carnevale, 2003). NeuronPM takes an existing set of Neuron model files, publishes them on a server, and runs them on client computers as a Windows screen-saver. Thus, it lets you lash together idle Windows machines to make a primitive grid that can rapidly map a large parameter space for your model. NeuronPM is designed to be easy to use and install--an attempt to make large-scale parameter analysis more widely available for neuroscientists.