There are industry guidelines for all the genres, such as romance, suspense, science fiction (hard science or not), and each publisher has guidelines, too. The best rule of thumb is to end a chapter at the end of a scene which both answers a question (either a small one introduced in the chapter or a big one which is part of the main plot) and entices the reader to quickly turn the page to the next chapter.
As to actual length, the numbers I've seen are word count rather than number of pages, and they run anywhere from 2,500 to 8,000 words per chapter, depending on the genre and that publisher's guidelines. And some famous writers get to trample all over those numbers. One of Ray Bradbury's last books had some chapters as short as a thousand words, but then who's going to tell Ray Bradbury he's wrong? Not me!
I know that's not much of an answer, but there's not a firm one, at least not one of which I'm aware. Most of the writers on these boards have a very good grasp of both when and how to end a chapter. At random, I present Female Hawk's "Trusting Me, Trusting You" series, where the chapter endings always provide local closure yet leave the reader drooling for more.
And she is not alone. AntiKryptonite's "Lethal Qualities" is another excellent example of this principle, as is Dandello's "Suddenly Blond(e)," which is due for another installment (hint, hint).
And it depends on the story, too. When I was working on "Rebuilding Superman," much of which took place in a courtroom setting, some of the chapters were longer than I would have preferred. But they needed to be, because there were a lot of pieces of information that I had to package together to make the story make sense.
To make a long post short (too late!), I think that a chapter needs to be short enough to hold in the reader's hands and long enough to say what the author needs to say.
