A post at The Economic Populist suggests unemployment from GM will get much worse:

I just had a truly frightening experience. During a conversation about the auto industry one of my colleagues who researches the auto industry told me that according to his calculations, the GM shutdown is going to send 250,000 off the job in Ohio.

This includes only the multiplier effect at auto suppliers, not any macro economic effect. For example, job losses at retail stores resulting from drops in spending are not included, nor are any further drops from other problems.

The post goes on to suggest that Indiana will see over 100,000 and Michigan a whopping additional 1 million in unemployment!