Over 70 airports world-wide are A380 capable today, and about 50 have had an A380 land and takeoff from them. Most do not have scheduled A380 pax service. In the US all the major airports are A380 capable (JFK, LAX, ORD, etc.) as well as some less obvioius ones like CVG and BDL. Given that the A380 requires shorter runway length than 747 to takeoff, and was designed to fit the same "box" as existing aircraft, this is hardly a surprise. Most large airports required minor changes for things like taxiway clearance (particularly for vehicle traffic and turnoffs) and sometimes for weight loadings. Not sure if any US airports have installed dual-level jetways (I actually boarded QF A380 at LAX but was in F which is downstairs and didn't notice if there was an upper jetway connected at TBIT).