  The critical temperature and the nature of the QCD finite temperature phase
transition are determined for Nf=2 dynamical flavors of nonperturbatively
improved Wilson fermions. The calculations are performed on large lattices with
temporal extents Nt=12, 10 and 8, and lattice spacings down to a = 0.075 fm. We
find the deconfinement and chiral phasetransitions to take place at the same
temperature. Our results are in broad agreement with a second order phase
transition in the chiral limit. The critical temperature at the physical quark
mass is found to be Tc = 174(3)(6) MeV.
