FlyNumber provides virtual numbers all over the world and can work with ANY VoIP provider.

If the Provider has a SIP uri ( that isn't firewalled or limited) we can send the calls there at no additional charge


You can easily set up our service with Callwithus. They've provided us their SIP URI to make things easier for you. You enter the username with Callwithus at the signup form and that's it. 

 

Callwithus

Callwithus
http://www.callwithus.com/