I posted this yesterday over at the Scratch forum I guess I should share it here as well.
Its a library I created for making it easier to use the Arduino as a Scratch board without having use a proxy program. At the moment it only supports input so that you can emulate a Sensorboard but I want to add support for output, ideally without changing the Scratch Imagehttp://www.geekstudio.co.za/files/arduino/scratchlib/Scratch1.0.zip
and heres a simpletest scratch project:http://www.geekstudio.co.za/files/arduino/scratchlib/arduino.sb
You just need to unzip into your libraries folder and import and possibly restart the IDE, once this is done you can run the Sensorboard example if you want to try it out quickly.
Inside Scratch you need to select the COM port your Arduino is using, this will be the Virtual COM port, and you right click on the block showing the variables and select the COM port that the Arduino is using.
If you aren't sure which port number that is because it changes sometimes, go into the Arduino IDE and check which port is selected there