Dialling Amsterdam from outside the Netherlands: 00 31 20 + number
Dialling Amsterdam from inside the Netherlands: 020 + number
You can make calls from post offices or public phone boxes. Most public phone boxes will only accept phone cards, which you can purchase at tourist information centres and post offices.
The main post office is located at Singel 250 . Open Monday-Wednesday and Friday from 09.00 to 18.00 and Thursdays from 09.00 to 20.00. They are also open Saturdays from 10h00 -13h30.
Not surprisingly with such a modern city, Amsterdam has loads of Internet cafés. Turnover is admittedly quite high among them and standards of equipment and connection vary.