I can't find a way to mouse over or right click Objects and their members and get more information on them than the members they contain (for objects) or the arguments they take (for methods).
Coming from a Java background whenever I have a question about anything in Sun's Java API, whether it be an object (like File, or SwingWorker), or a method (like substring(), or readLine()), I can access their documentation in-line with either a ctrl-space or right click in either netbeans or eclipse.
Is there some way to do this in Xcode for Apple's Objective-C/Cocoa API?
Option-click the thing you want to know more about. When you hold down option (alt), you should see your cursor turn into a question mark (when hovering over a symbol that can actually provide documentation). Clicking an item brings up the relevant docs in a popover. You can drill further in using the links at the bottom of the popover.