We present some recent developments on model building for neutrino masses and
mixings. In particular, we review tri-bimaximal neutrino mixing derived from
discrete groups, notably A4. We discuss the problems encountered with extending
the symmetry to the quark sector and with Grand Unification.Comment: Talk presented at the XII International Workshop on Neutrino
Telescopes, March 6-9, 2007, Venice, Italy. 23 pages, 2 figure
