From their web page:

IOM is conducting on-going, in-depth assessments of recently displaced persons throughout Iraq. Monitors use Rapid Assessment questionnaires to gather information from IDP families, the Ministry of Displacement and Migration (MoDM), IDP tribal and community leaders, local NGOs, and local government bodies. Based on a database of this information, IOM disseminates bi-weekly, bi-annual, and annual reports containing updates, statistics, and analysis on displacement.This information assists IOM and other organizations in prioritizing areas of operation, planning emergency responses and designing long-term programs.

June 2008 updates and much more solid information can be found here http://www.iom-iraq.net/library.html#IDP

Creon