Postal Authorities On The Web:
Aland Post (Finland)
Aruba 
Australia Australia Post
Austria Postal Authority
Canada Post Corporation.
Dutch PTT
Finland Post Ltd
French Ministry of Postal Services, Telecommunications and Space
Deutsche Post AG Online Germany
Icelandic Postal Authority
Indonesian PTT
Ireland An Post. Ireland's National Postal Service
Italian Postal Authority
Japan Ministry of Posts and Telecommunications
Jersey Post Office
Latvia Post
Luxembourg Postes et Telecommunications
Netherlands Antilles Postal Authority
New Zealand Post - Philatelic Bureau
Sweden Post
Switzerland's PTT (Postes, Telegraphes, Telephones)
United Kingdom Post Office
United Nations Postal Administration
United States Postal Service
