Processing, an open-source programming tool developed by Ben Fry and Casey Reas at the MIT Media Lab and elsewhere, is a wonderful freeware artmaking tool available for download from the Processing website. It works on Mac OSX, Linux, and Windows platforms. Because Processing is open-source, many interested programmers are writing libraries that work with Processing to extend its capabilities, for instance, to sound manipulation, video analysis, and serial communication. The last of these is especially useful with the EZ I/O, and is relatively easy to set up.
Macintosh System X: Once you've downloaded Processing and installed it, you'll need to do two other steps to get Processing ready to work with your hardware.
Further instructions for setting up the serial port are included in the Processing sketch itself.