Thank you very much. This was a great article. I had an old arduino duemilanove plus bread board, cables and pots lying around. So I grabbed them and built it myself. It went absolutely flawlessly and I had a lot of fun doing it. I will buy some interesting sensors next and use them as midi input. Good times. :)

Great article Joshua. I made this on a breadboard last night and can give you some extra tips:
Open up the Arduino Connection Kit in a MIDI track.
Drop the soft synth of your choice into the instrument where it says "drop instrument here"
Right click on the synth title and select "Group" - an Instrument rack will appear
Click on the curly logo under the Instrument Rack on/off button - it's called "Show/Hide Macro controls"
Click "configure" on your soft synth and then click on the controls you want to control on the main VST GUI e.g. VCO, VCA, Osc, etc. They will populate under "configure". Click "configue" again.
Right click on a new configuration and select the macro control you want to use with it.
Click on a "MAP" in the Arduino control and then click on the Macro dial you want to control with that map.
You will then be ale to control your VST with the Arduino pots! Voila

So I just found out if I add another Arduino and open another instance of the connection kit on the same track I can add another 6 analogue maps. I just made sure the port was set the other Com port and not the same as the first Arduino. Looks like this is going to be extremely useful.

I was wondering what if you needed to retro fit your arduino for other purposes? I assume the firmata sketch is communicating via serial.. Is there scope to use a method like this via ethernet or something else to free up serial for visualisation in processing or similar?

This is a great tutorial, Im having trouble getting this to work with an Arduino 101. Has anyone tried this with the 101?

Guys! great tutorial, great video bt a silly question. If I plug an arduino mega is it going to automatically read the extra analog ports?