Do you have limited free monthly minutes or just want to know more about your call history?
If yes, the Call Log app is what you need.
It provides you with a better overview of your calls to keep track of overall call durations. Filters allow you to look at predefined and custom date ranges to find out how outgoing and incoming calls are distributed over time.
The statistics overview gives you an idea what the average call durations are. The monthly overview lets you know then overall length of your calls. You can use this for instance to find out if your free monthly minutes are enough or you regularly exceed them. The weekly and daily overviews show you how your calls are distributes in more detail. The same information is available for incoming calls as well.
In addition the app includes a home screen widget showing the overall outgoing call duration for the current month. The widget changes color in case the duration exceeds the limitations you defined allowing you to keep an eye on your free minutes.
Limitations: The app does not (yet) distinguish between foreign calls, local calls and calls to your mailbox. Cumulative durations are based on the data in your phone log and may slightly differ from the data of your phone company depending on how they measure call durations.