Does everyone in the world but me know about Cramster.com? Basically it's a website that includes as many answers to textbook homework problems as they can possibly put together. As far as I can tell it works on a Wiki system, where members submit the various solutions, although there are apparently also "expert" solutions. Odd-numbered solutions are available for free, but you have to pay to see the even numbers. Nothing there for my GR book, although there were some for Jackson's E+M book, and plenty for Halliday/Resnick etc. Not really sure what to think about sites like this. Part of me (a big part, actually) couldn't care less about whether students do their homework, and for that matter thinks that grading is a complete waste of time. What matters is whether or not the students have learned the material, not how they perform on some formalized exercises. If they get perfect grades but don't learn anything, ultimately they're the ones who will suffer; even if they get into a better grad school thereby, they'll just find that their fellow students are much better prepared than they are. But then there is the whole "fairness" thing, which sadly does matter. There is a set of rewards -- like good jobs and/or grad-school admissions -- that we base on grades, and they should go to the most deserving students. So, unpleasant as it might be, we have to evaluate them somehow. But in this brave new world, it would probably be wise to make up original problems rather than using the ones from the back of the book.