I know it would ONLY work within the app and not in the actual settings page, but it would be great to have a button under a text field that would look something up from the Internet. It would trigger a function and then listen for a completion trigger, all the while, showing a "busy" interface.
For example: I have a tax rate text field in my settings. It would be awesome for me to be able to let the user tap a button, use the iPhone's GPS to locate them, then look up the local sales tax for wherever they're at, and then auto-input the preference for them.
This setting would not be in the main Settings.app listing, but would be a great enhancement to allow the users a better experience within the app.