Siphon Softphone for iPhone or iPod Touch G2

For Jailbroken iPhone or iPod Touch V2
Search cydia for Siphon (Free softphone app that works on 3G, WiFi, speakerphone, G711, GSM, G729, G722)

Jailbreak howto

Download and Install Siphon (free)

Search cydia for siphon and install it

Siphon Fonosip.com Configuration

Settings

Username: 812345
Password: password
Server:   fonosip.com

all other options leave as default or blank
as shown in the settings screenshots below

For best call quality also enable Codec G729 on 
"phone settings" -> "codec" -> "G729"

Screenshots

Call Screenshots

Settings Screenshots

The parameters for several SIP providers are described on this page.

Misc

History

Home of the World's first free SIP/VoIP application for iPhone and iPod Touch 1 and 2.

Siphon SIP/VoIP project is the first in his category that works on iPhone and iPod Touch 2 with headset for all SIP providers. It is a native application approved running on 2.X using internal micro/speaker and headset.

The Application supports the SIP standard, preserving compatibility with hundreds of SIP providers and offers a GUI which preserves the apple design of native iPhone applications.

You need a microphone with a HW key inside "approved" by Apple. Such as iVoice III from Macally or ThumbTracks micro-microphone. Or the Apple earphone with integrated mic.

fonosip siphon config utility add-on

fonosip siphon config help

fonosip siphon skin

Siphon home site