The Call Timer shows the duration of the current call. It is visible only while a call is active. You are not charged for call-time in a call to another LIVE user, but you are charged a per-minute rate for calls to "outside" telephones. The per-minute rate is shown to you when you place a call to an outside telephone, so you can decide whether or not to go ahead with the call. You can review the durations of your past calls by viewing your Call Logs.