Developers that have a CUDA codebase and wish to be using OpenCL, here is a small tool to help you make that move. Swan is an open source GPL’d command line tool that aids the reversible conversion of existing CUDA codebases to OpenCL. A complete list of what Swan can and cannot do is available on their website.
This star and planet charting iPhone 3Gs app uses your current global position, heading, and accelerometer data to draw a current picture of the stars and planets around you. A small portion of the code is GPL licensed, but the bulk is BSD-style license or less restrictive. The app and source code make a great learning tool.