http://www.twilio.com/blog/2013/03/build-a-twilio-hard-phone-with-sip-from-twilio-raspberry-pi-asterisk-freepbx-and-the-obihai-obi100.html?utm_source=newsletter&utm_medium=email&utm_campaign=April (http://www.twilio.com/blog/2013/03/build-a-twilio-hard-phone-with-sip-from-twilio-raspberry-pi-asterisk-freepbx-and-the-obihai-obi100.html?utm_source=newsletter&utm_medium=email&utm_campaign=April)
Here is a blog post using Twillio Raspberry PI and an OBi100.