The FBI has released its "2007 Mortgage Fraud Report." Its a fascinating study and quick read. It covers all the basic types of mortgage scams and cites statistics from several different sources. An excellent overview of the scope and magnitude of the problem, including a particularly fascinating description of "short sale" and "mortgage rescue" scams that are particularly popular in the current market climate.
Illinois (again), makes it into the national top ten for states most effected by such criminal activity.