...as of 3 Dec 06, reporting on numbers since 22 Feb 06, this report states that there are 40,896 families displaced. That's less than half the number Merv referred to in his post debunking the scale of IDPs back in April, but still a significant number. The file at the link breaks the numbers down by origin and location to which displaced, and also notes whether the IDPs are primarily Sunni or Shi'a. There is also a narrative summary of situation by governorate:

Emergency Assessment: Displacement Due to Recent Violence Central and Southern 15 Governorates