I've looked around in a number of places and I have found several blog entries on setting up IPython notebooks to work with Spark. However since most of the blog posts have been written both IPython and Spark have been updated. Today, IPython has been transformed into Jupyter, and Spark is near release 1.6.2. Most of the information is out there to get things working, but I thought I'd capture this point in time with a working configuration and how I set it up.
I rely completely on Homebrew to manage packages on my Mac. So Spark, Jupyter, Python, Jenv and other things are installed via Homebrew. You should be able to achieve the same thing with Anaconda but I don't know that package manager.
Make sure your Java installation is up to date. I use jEnv to manage Java installations on my Mac, so that adds another layer to make sure is set up correctly. You can download/update Java from Oracle, have Homebrew