I need a offline version of http://developer.apple.com/library/ios/navigation/
Does something like this exist? thank you
You've already got an offline version of the Doc, if you have Xcode installed in your system.
In Xcode, goto Help --> Developer Documentation. Shortcut: Option + Command + ?. This will show you the documentation page loaded in Xcode itself. Select the Home button at the top of the toolbar. It will show a drop down list of reference libraries available. Select iOS library from the menu. It will show you the page you want.
In Xcode, Option + Double-Click on a symbol: Opens the doc for the selected symbol in a small window. Clicking on the book-like-button, the second button from the top-right corner of the window opens the reference page of the symbol. That button is enabled only if the documentation available for the symbol.