Regional organizations also provide information on their activities:

African Union (AU)

Asia Pacific Economic Cooperation forum (APEC)

Association of Southeast Asian Nations (ASEAN)

The Commonwealth (Britain and nations that were former colonies, but remain close to Britain economically and politically)

Economic Cooperation Organization (ECO) Organization of Central Asian states, from Turkey to Kyrgyzstan

Economic Community of West African States (ECOWAS)

European Union (EU)

North Atlantic Treaty Organization (NATO)

Organization for Security and Cooperation in Europe (OSCE)

Organization of American States (OAS)

Organization of the Islamic Conference (OIC)

Organization of Petroleum Exporting Countries (OPEC) -- a cartel of oil producing nations that spans several regions. 

Pacific Community (Pacific Island nations and territories)