Sorry, saw this thread and just have to hijack it a little. Synaesthesia is quite real... I have it. I have yet to find a program that reacts to music as I "see" it, but the programs do give an idea for what it's like. There are quite a few sites out there with related articles about it. Some people are crazy, seeing what they taste and smell, etc. I just see music and have colors for letters, numbers, and words. Sometimes I can force a smell to look a certain way but it isnt inherent.
Like I said, just had to hijack!