Let's not forget that the EU is first and foremost a customs union.
The new Customs Code - Regulation 450/2008 - has been adopted by the Parliament and Council and published recently. It is quite a monument and an achievement. For a brief and general explanation of the customs code, see here.
The provision on its entry into force is quite complex: Some provisions come into effect on June 24th 2008 to give a basis for implementing measures, the rest on June 24th 2009 at the earliest and June 24th 2013 at the latest, and one provision - Article 30§1 - on January 1st 2011.
A striking feature of the new Code is the amount that is left to the Commission to work on in the implementing measures.