@anon31514-- A regional integration agreement is when neighboring countries to establish common rules and even institutions. The goal is to increase cooperation in political and economic areas. It can also involve cooperation in security matters or environmental issues.
Since this is also an economic arrangement, it also involves easier trade between countries in this regional integration. A free trade agreement on the other hand, is only an agreement for trade and nothing else. It is not permanent and can be discontinued. Moreover, countries in free trade agreements don't have to be neighbors.