To make a call you can search for a person and Click call for his or her profile. If a person didn't insert contact phone number when registering, you won't be able to call. Please use other ways to contact members.
Yes. When calling a call is forwarded to a server and then to a recipient phone so that none of you sees the contact details. Though you do not need any special equipment for that and may use usual cell phones.
Money is taken from your account at a site depending on the distance you're calling to. If there's not enough money on your account, you'll be able to add points from a site.
Yes. you can see your calls with users' data in Calls section in Main menu.