On the 13th of December 2007 the heads of states and governments of the European Union signed the new EU Reform Treaty from now on called the Treaty of Lisbon.
Member States will now need to ratify the new treaty; each Member State will take its own decision as to whether to do this via a referendum or via Parliamentary ratification. The ratification process should be complete by 2009, allowing the new treaty to enter into force before the European Parliament elections of June that year. However, at the moment it seems that the January 2009 deadline by which governments had hoped to have the treaty in place is being missed.