I have just installed the free Siphon application on my iPhone 3G, and set it up top work with my FPL account.
It works really, really well. This app is great because:
- It supports DTMF (unlike Fring and Nimbuzz!)
- Supports the G729 codec
- Free
Since my iPhone is jailbroken, I can even leave Siphon in background, lock the phone, and receive calls!
Here's my settings.
Main settings screen:
From the main screen, press "Advanced settings" to setup the proxy.
From the main screen, press "Phone settings", then "Codec" (also in Phone Settings, I turned on Keypad sound, because I like it.)
That's it! Works great.