Although I have no experience with residencies as I am just applying to medical school now, you can search various residencies and their working hours <a href="http://www.ama-assn.org/ama/pub/category/2997.html" target="_blank">here</a>. Check out the web sites for the various residencies to find out more information. I found it pretty informative just learning about the different residencies.
Mpp is right - FREIDA is a good place to start. You might also read some of the reviews of residency individual residency programs on the main SDN page. Reviewers give an idea of hours on different rotations etc.