You could probably also just use an emulator like VMWARE or
Sun Virtual Box (FREE) or rather than installing windows directly on your mac, and mount the kindle as a share in the virtual machine, would be pretty easy... You can actually have it take control of USB devices directly as well if you want (thought this would not be necessary in the case of the kindle)
Basically you just create an image, install windows on the VM, and you can run windows programs and such without rebooting, everything runs from within the application.