Woo! Only a few lines of code, thanks to the Arduino Midi library! Will post a video tomorrow, bloody happy right now. I think some form of filtering is definitely required as the values tend to be quite jumpy - more tomorrow!
Note to self: MPX5010GSX - 5V breath controller, with output at Vfs 5V! This looks like the ideal breath sensor to match with the Arduino... only needs 3 connections, Vcc, GND and Vout. Aiee.... wish I'd knew about this earlier :( Would have saved me alot of time and £££ figuring out about the instrumentation amps and power supplies. On the flip side, I did learn a fair bit there, so :)
MP3V5010 is another option, but it is smt, ick.