Algorithmic and technical progress achieved over the last few years makes QCD
simulations with light dynamical quarks much faster than before. As a result
lattices with pions as light as 250--300 MeV can be simulated with the present
generation of computers. I review recent conceptual and numerical progress in
this field, with particular emphasis on results obtained and difficulties
encountered in simulations with significantly smaller quark masses with respect
to previous computations. I also attempt to compare physical results for pion
masses and decay constants available to date in the two-flavour theory with
expectations from chiral perturbation theory.Comment: Plenary talk given at XXIVth International Symposium on Lattice Field
Theory Lattice2006(plenary), Tucson, Arizona, 23-28 July 2006. Submitted to
PoS in October 200
