AV8R:
You can download the most current MPGuino version
here.
You change the briteness settings at "bite brightness", very close to the top. If I remember correctly, 255 is off, 128 is full power. I only have three settings, 255, 245, 128. This allows me to turn it off, have a very low power for night time driving, and a bright setting for daytime driving. I am also using the blue LCD, which doesn't work as nicely as the yellow/green ones.
You will need arduino version 0011 to make this work, version 0012 will NOT work.
Arduino 0011 (
release notes):
Mac OS X,
Windows,
Linux.
Here is the page for
"how to" install the programs on it. Not so bad. Here is a
link to Post #46 of this thread. cmags does a good job of describing the process for installing the software onto the iDuino. I would guess it would be very similar, especially since the iDuino and the MPGuino Kit are both made by Fundamental Logic.