What is an IGO?  An IGO is an organization composed primarily of sovereign states (referred to as member states), or of other intergovernmental organizations.  What is an NGO? A NGO  is any non-profit, voluntary citizens' group which is organized on a local, national or international level.

NGO Voice
http://www.ngovoice.org/index.php?page=121    
VOICE stands for "Voluntary Organizations in Cooperation in Emergencies". It is a network representing 82 non-governmental organizations (NGOs) active in humanitarian aid worldwide, who are based in 19 European countries.   Members are drawn from European nations.

Worldwide NGO Directory
http://www.wango.org/resources.aspx?section=ngodir  
Select Western, Southern or Eastern Europe.  A list will be generated which may be sorted by country and area of activity.

IGO Custom Search Engine
https://www.google.com/cse/home?cx=006748068166572874491:55ez0c3j3ey
This Google Custom Search Engine (CSE) is a project of the International Documents Taskforce (IDTF) of the American Library Association (ALA). The IGO Search searches across hundreds of IGO websites.