Connect the dots: Amazon -> Twilio -> OpenVBX.
Amazon is the cloud infrastructure where Twilio voice and SMS apps are running, while OpenVBX is the developer- and business-friendly interface to Twilio.
Voice. Conferencing. SMS. You may check the status of Twilio here.
With Twilio SMS, there is no contract. Pay as you go, 3cents per message. Web programming required (HTTP/XML processing). Or if you want, you may also download OpenVBX and host your application at your own premises but still, voice and SMS processing takes place via Twilio.
Competition heats up (Grasshopper and OneBox). There’s also Tropo from Voxeo. And with IM, Twitter and XMPP integration to boot!