My company needs a Sip agent/dialer for general mobile phones (all-rounder).
We need it for our clients to enable them to register with our Asterisk box (Elastix) in order to make and receive VoIP calls while on GPRS, Edge, 3G etc. The codec should be g729 or similar.
We need the clients to download the pre-configured software to their phones, enter their account name and password, and they should be able to make/receive calls. NO other settings should be necessary.