gistfile1.cs

NSError err;
ab = ABAddressBook.Create (out err);

if (err == null) {
    ab.RequestAccess ((allowed, err1) => {

        if (allowed) {
            var people = ab.GetPeople ();
        
            foreach (ABPerson person in people) {
                Console.WriteLine ("{0} {1}", person.FirstName, person.LastName);
                var phones = person.GetPhones ();

                if (phones.Count > 0) {
                    foreach (var phone in phones)
                        Console.WriteLine (" {0}, {1}", phone.Label, phone.Value);
                }
            }
        }
    });
}