IGM Reionization and 21 cm line observations

With the advent in the near future of radio telescopes as LOFAR, a new window
on the high-redshift universe will be opened.  In particular, it will be
possible, for the first time, to observe the 21cm signal from the diffuse
Intergalactic Medium (IGM) prior to its reionization and thus probe the "dark
ages".  In this talk I will discuss about the theoretical modeling of the
reionziation process, the observability of the 21cm signal from the diffuse IGM
and the efforts ongoing within the LOFAR Epoch of Reionization Working Group.