the author of this app says:
YourDialer is an universal VoIP dialer, which supports a wide range of VoIP services. Simply log on using your excisting credentials and start saving on your national and international calls anywhere you go, anytime you want! Most of the cheapest providers are already supported.
To start saving on your mobile calls, simply install our FREE dialer from the app market. If you don't have an account yet, register with one of the supported brands and buy some credit. All you need is the YourDialer app and a 3g or WiFi connection.
What's New in version 1.0.1
Some bug fixes
- Requires iOS 3.2 or later