Thank you so so much for your replies. It's great to have people to steer you in the right direction!
I'm looking into the Processing/Minim route at the moment. BUT surprise surprise I've hit a hurdle already (It must be so frustrating dealing with newbies .... sorry!)
Would you mind clarifying what the processing-Arduino link is? I've been searching everywhere, but everything online seems to assume basic knowledge (which I clearly don't have lol). Am I right in think that I should use the Arduino Environment to control the actual board (pull in light sensor information), then pass this information to Processing - where the audio will be controlled? I've thought for the last few days that Processing was something used to control the Arduino board directly :-\
My next hurdle (I have a feeling this is going to be a long journey!) is getting Processing working on my computer. The only guide I can find is here: Arduino Playground - Processing. It seems pretty clear (bonus), but unfortunately it doesn't seem to pan out. I've downloaded the processing-arduino.zip as stated, and un-zipped it, but there is no 'Firmata' in 'Examples' ..... or anywhere else for that matter. Firmata seems to be key in getting the arduino and processing communicating with one another, so I'm not sure what to do!! Do you have any advice or suggestion please?
Also, one other quick question, the instructions on arduino.cc keep referring to the Processing Sketchbook e.g. '1.Unzip the library and copy the "arduino" folder into the "libraries" sub-folder of your Processing Sketchbook.' Does this mean the main Processing directory that I downloaded?
Thank you!!!!