My boyfriend worked for the same company during 2006 in two different states. In October of 06, his company moved him from NY to IL. He received his W2 and all wages were reported in NY for 06. Does he need to get a corrected W2 to reflect his change of address and state? Or, should he file just for NY and correct the address going forward?

File his tax returns and correct the address going forward.

Also, even though no taxes were withheld, he is also obligated to file an Illinois tax return and pay taxes on the money earned in Illinois as a part-year resident.