Your iPhone needs to be jailbroken and you basically replace some files with the patched files. Hopefully there’s no backdoor in them!

1) You must be running a Jailbroken iPhone / iTouch
2) Install original Fring via iTunes App Store.
3) Now SSH into your iPhone / iTouch; remember root / alpine
4) Find Fring.app under root var/mobile/applications
5) To find the Fring.app, you then need to click on the most recently installed folder which will be your original Fring and inside should be the Fring.app
6) Unzip the files
7) Delete or rename the original Fring.app on your iPhone / iTouch
8 ) Copy the extracted 3g Fring.app from the zip folder across to your iPhone / iTouch either via the WinSCP (PC) or Yummy FTP (Mac).
9) Now you need to set the permissions. This is easy so please do make it more complcated for yourselves. ALL the files within the 3g Fring.app replacement must be set to 755 (Yummy) or 0755 (WinSCP). You should see all the files being altered as it goes through the process of changing the permissions.
10) When I tried it, it worked immediately after changing the permissions without a reboot but if it does not work then please reboot.

Google for “Fring Patched for 3g” – it should be on some popular torrent sites right now.

Screenshot of Fring over Rogers 3g allowing SkypeOut