In China and Hong Kong some providers offer to route a phone call through an IP network if you dial a special prefix before the actual phone number. As the routing through an IP network is cheaper, the rates for a call is in most cases way cheaper than a regular call. It is however very inconvenient as you have to initiate each call by typing the prefix and number instead of just selecting a contact from the address book. I figured out that it is possible to use the application BerryDialer, which is originally intended to use callingcards, for this purpose.
China Mobile IP Prefix (domestic long distance calls): 17951
(Note: to use this prefix, phone numbers must be stored without country code as China Mobile does not like a county code in domestic ip calls. The BerryDialer support told me they will add a feature to ommit country codes in a free update version soon.)
China Mobile IP Prefix (international calls): 12593
(You have to register for international calls first)
How to configure BerryDialer for this:
Now you can enjoy cheap IP phone rates without losing the comfort of easy dialing through your address book. BerryDialer is available for $19.99 at MobileSoftMarket.
Note: This is only an example for China and Hong Kong providers. Such a “cheap call-prefix” will most probably also be available in other courntires / with other providers. If you know, please leave a comment.