  Large inhomogeneities in neutral hydrogen in the universe can be detected at
redshifts $z \leq 10$ using the redshifted 21 cm line emission. We use
cosmological N-Body simulations for dark matter and a simple model for baryonic
collapse to estimate the signal expected from structures like proto-clusters of
galaxies at high redshifts. We study: (i) the standard CDM model, (ii) a
modified CDM model with less power at small scales, and (iii) a $\Lambda+$CDM
model in a universe with $\Omega_0 + \Omega_\Lambda = 1$. We show that it
should be possible for the next generation radio telescopes to detect such
structures at the redshift 3.34 with an integration of about 100 hours. We also
discuss possible schemes for enhancing signal to noise ratio to detect
proto-condensates at high redshifts.
