To get everything up and running, you'll need to get Python and PyUSB installed and grab this nice Python XXTEA implementation. I've also got a quick Windows only Python module implementation that you can use to control the Cricut as well. I coded up a quick Python demo script that's a Logo interpreter for the Cricut that's included with libcutter.
Right now all our experimentation has been with Cricut personals at firmware revision 1.34, but I'm hoping it'll work with other models as well. Libcutter's goal is to be a nice cross platform library for controlling the Cricut and potentially other similar devices. Check out the Cricut Wiki I started for more details on the protocol and check out the libcutter project on GitHub if you want to start writing your own control software. After a bit of work and help from fellow Hackerspace members, we managed to figure out how to talk to the Cricut.
