I'm catching up on my blog-reading, and Udi Dahan's Programmers don't make projects fail is a keeper. Make sure you read to this part:
My philosophy is followed with an operative task: If you ever have to do more than 2 hours of overtime in a week, let me know.
I understand the 2 hours of overtime, although I'm not sure I agree with it. But any more than that, and you've got the first indication of a project in trouble.