Has anyone tried this device: ARTECH AD102
Total with shipping is about $50USD.
It uses USB HID class (so no driver needed) to report in/out calling to a computer. The SDK is open but written only for Windows at the moment.
My primary interest in the device is that it supposedly supports call waiting caller ID but I can't get that feature to work with their demo software. I reported this to ARTECH but haven't gotten a solution yet.