I want to write a software to allow the parents to set a limit to their children phone calls.
I need to lock some phone capabilities with a password after the limits are reached.
I'd like to know how I can block phone calls from being made, and receive. And if it's possible to set a white list for emergency calls (e.g : the teen can't call friend after midnight but can call 911).
Without modifications to the Android firmware, I do not think this is possible. Android's focus is to give ultimate control to the user, and in your case, the user is the child, not the parent. Hence, there are no great hooks as of Android 1.5 for parental controls, enterprise lockouts, filtering proxies, or similar features.
You might be able to toggle on airplane mode, which shuts down all radios, though the user could just toggle it back off, forcing you to have to turn it on again...
Not 100% sure, but You could create an instance of BroadcastReciever that would intercept
android.intent.action.NEW_OUTGOING_CALL
intents. Then, based on rules defined by You, it would be possible to drop this intent (blocking the call) or execute it by system