Installing ATtiny45 / ATtiny85 support in Arduino

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.

Don't have / use Mac, but since this is Java, I think usability wise, it should be similar to what we have on Linux / Windows.
Just create a new empty sketch and try to save it. The file-system browser window that opens up, note the path where it saves your new sketch. That is your sketchbook folder.

• Start the Arduino IDE

• Click the menu item File / Preferences

The sketchbook location is at the top.