The https://freephonebox.net service has now gone live. This is a great way for people without a SIP account to call those who do have one (like all the Debian Developers who got SIP on Saturday) using nothing more than a web browser (no plugin required).
Not just voice, webcams too
Free calls made possible by free software
The service itself runs on free software, including some of the following components:
SIP users who want to receive calls from freephonebox.net users simply need to make sure they have SIP over TLS enabled for their domain.
Calls from the phone box are anonymous but will always appear to come from the SIP address sip:email@example.com.
For Debian SIP users
To make and receive WebRTC calls quickly and reliably: