EU Recreational Craft Directive - Regulations regarding EU members' registered boats.
EU Visitor Visas - List of countries whose nationals require a visa.
List of Member Countries - Current cuntries in the EU.
VAT - Information on European Union Value Added Tax, including exemptions for non-EU yachts.
For more information about the European Union, try their "user-friendly" website at http://europa.eu/index_en.htm
Many officials in European countries expect to see some type of certificate of sailing competence even though the skipper's flag state does not require them to have one. Many charter companies will also require one.
For both Europeans and non-Europeans obtaining an ICC (International Certificate of Competence) is a useful way to go. This has the added advantage that, by completing an online endorsement CEVNI (Code Européen des Voies de Navigation Intérieure), a skipper is licenced to travel on the inland waterways of Europe.