As reported in this blog on June 2 this year, AJCEP (Agreement on Comprehensive Economic Partnership among Japan and Member States of the Association of Southeast Asian Nations) was signed in April this year with 11 countries in ASEAN.
Now it was announced by Japanese government that this AJCEP will be effective from December 01, 2008. After this date, AJCEP will be implemented with the countries who made notification. With regards to the ASEAN countries which will make the notification later, the Agreement will enter into force subsequently in accordance with the stipulations of the Agreement.
(Source: Ministry of Foreign Affairs of Japan http://www.mofa.go.jp/announce/announce/2008/10/1184016_1060.html)