The most annoying thing on the iOS is inability to set default applications. For instance there is no way to set Google Maps as default mapping application on iPhone. We all know how bad the Apple Maps is, so is there any way to set the more capable Google Maps as default mapping app? Yes, if you have a jailbroken iPhone.
There is a utility called MapsOpener that changes the default maps app to Google Maps. Using this utility all links to maps will be directed to the Google Maps and even Siri will use Google app instead of Apple Maps.
Before you install the MapsOpener tweak, make sure you have Google Maps installed. No icon is added to homescreen and there are no settings to configure too. All map links are simply redirected to Google Maps.
Also check out how to change default web browser on iPhone. Search for MapsOpener on Cydia. It is a free tool.