This is an article from last week (4/25/2003) about the Tuwaitha Nuclear Research Center. In this article, there's brief mention that looting evidently took place, but not what was taken. The MEMRI article from today (5/1: http://www.memri.org/bin/latestnews.cgi?ID=SD49703 ) goes into more detail about what was taken, and how the radioactive material is steadily contaminating civilian homes in the area.

Washington Post: Iraqi Site That Contained Uranium Was Looted After War