you cant port games/apps from android to iphone or iphone to android, because the apps are two different languages. Ask the developer of x construction to make one for iphone, im sure they wouldnt mind because it would mean more money usually.
I am creating a clone of X-Construction, and it will be a universal app for iPhone, iPod Touch, and iPad. It's going to be called "Link", and should be available sometime in mid-December 2011.
Here are the links (including the link to "Link" aforementioned).
They are all very similar to x-construction (bridge building, etc.) but all have different twists to the game play. For example, in Monorail, users are limited by $ available rather than by amounts of construction materials.