C/C++
Adventures in OpenCL - Tutorial series for getting started with OpenCL in C/C++
Python
PyCUDA - module for calling CUDA from Python
PyOpenCL - module for calling OpenCL from Python
Atomic Hedgehog - cl.oquence module, abstraction of OpenCL in Python
PyFFT - PyCUDA and PyOpenCL implementations of the Fast Fourier Transform
Infrastructure
Amazon Web Services GPU Cluster Instances