By Chuo Taxi Service - highly recommended
The taxi service offered by Chuo Taxi is the easiest way to travel. Chuo Taxi will meet you at Narita or Haneda Airport arrival displaying your own name card. Bookings are available from 1 person in a shared van or you can charter a private van for larger groups. Please reserve well in advance especially during the peak season.
http://www.chuotaxi.co.jp
http://www.chuotaxi.co.jp/publics/index/10/