Im trying to Install ATtiny45 / ATtiny85 support as per the guide at MIT Hight-Low tech
But cant find my sketchbook folder????
Download: ATtiny (from this GitHub repository)
Locate your Arduino sketchbook folder (you can find its location in the preferences dialog in the Arduino software)
Create a new sub-folder called “hardware” in the sketchbook folder.
Copy the attiny folder from inside the .zip to the hardware folder.
Restart the Arduino development environment.
You should see ATtiny entries in the Tools > Board menu.
I have arduino 1.0, and am on a mac....... =(
Moderator edit: link corrected.