looking for free inbound VOIP service with open source based

I am looking for the kind of VOIP service, which can give me the room to test and enhance couple of the project.
The service must be the free inbound call, and the client side is open source based (such as SIP, IAX protocol support), it should give me the flexibility to make my own version of the client, otherwise, it will not be what I am looking for.
Please share me with your experience, and kindly give me some suggestions.
Thanks.


Dragondad

Sounds like you are describing VOIPUSER ! We exist to test, experiment and play with VOIP.

If you have a specific project in mind or are working on a mash up or a particular application then either post some info here or PM one of the admins or mods. There is an amazing amount of combined experience here on the forum, could be we can help, if what you want to do benefits the existing community then we could take a look at incorporating it.

Over to you