Earlier this year I wrote an article on Real-Time Ray Tracing on the Playstation 3 Cell Processor. MIT is offering a course on Multicore Programming on the PS3. One of the examples presented is the Blue Steel Ray Tracer.
Earlier I also wrote an article on Four-Dimensional Cellular Automata Acceleration Using GPGPU. The University of Illinois at Urbana-Champaign is offering a course on Programming Massively Parallel Processors featuring GPGPU programming on NVIDIA CUDA hardware.
Currently applications must be written specifically for the Cell, conventional multi-core CPUs, or GPGPU. Several organizations are working to develop a common programming model where the same application code could be compiled to run on any of these. One such system is from RapidMind. It's programming model is much like the use of OpenGL within a C++ program. Arrays are defined using RapidMind container types (like OpenGL graphical types), and then embedded programs are invoked on them (like OpenGL Shading Language).