Voxeo have just announced a new SDK called phono which looks pretty interesting. At it’s core it seems to be a flash based softphone admittedly of which there are others around. However a fair bit of work seems to have gone into the programmability of the softphone and it’s free to download and use.
I haven’t had that much time to play with it yet but I have been able to place calls successfully with it. Entering sip:firstname.lastname@example.org in the call box on the Phono main page will call a demo number through sipbroker for the ever present monkeys. I’ve noticed on a couple of calls I didn’t get any audio but refreshing the browser, which would re-initialise the flash softphone, fixed that. Most likely an issue with my NAT timing out whatever sockets the softphone is using.