The IceTop air shower array is the surface component of the IceCube Neutrino
Observatory at the geographic South Pole. The combination of IceTop and IceCube
provides a new and powerful tool to measure cosmic ray composition in the
energy range between about 300 TeV and 1 EeV by detecting the electromagnetic
component at the surface in coincidence with the muon bundle in the deep
underground detector. The paper will give an overview of the current status of
the detector and the first physics results will be presented.