I just finished the Google CSE article I started a couple of weeks back. It was an interesting project, mostly due to the fact that I have never worked with the Google search API before and it was enjoyable to learn something new.
Hopefully you find it useful. When I was putting the code together, I found there to be a distinct lack of articles or documentation on the Custom Search Engines. Hopefully this helps someone. Then again, Google will probably EOL the JS CSE API in the next few months and I will have written the article for my own benefit. Ah well..