the author of this app says:
Telicost measures your data usage and compares it against your telecom plan. It will provide alerts for threshold crossings as you use up your data plan helping you avoid costly overages and will also alert you to roaming. You can also use Telicost with Intelicost, which works with a central server providing alarms to a telecom manager in charge of multiple devices.
Telicost requires multitasking support and will not run properly on other devices.
What's New in version 2.0.0
- Added support for compatibility with portal services
- Bug fixes
- Requires iOS 4.2 or later.