Most of their money comes from Housing and Urban Development, through programs that provide money Section 8 Housing Assistance, the Fair Housing Initiatives Program, Housing Counseling and Self-Help Home Ownership or Resident Opportunity and Supportive Services grants.
A cursory search on FederalSpending.org from fiscal year 2000-2008 shows ACORN received more than $12 million in grants and loans from HUD. A cross-agency search for ACORN yields more than $41 million in government grants and loans to ACORN, but that includes other groups with "ACORN" in the name.
I've been working on a master list (sorting the big ACORN from the little ACORNS), but the going is slow. This is a good starting place.
ACORN takes our tax dollars through government grants and programs and then submits hundreds of thousands of fraudulent voter registration cards---actions that costs thousands more in OUR tax dollars to clean up.
We should at least know how much money they are taking from us.