  We have performed magnetoresistance (MR) measurements of granular
ferromagnets having lateral dimensions smaller than 0.5 $\mu$m and containing a
small number of grains (down to about 100). Compared to macroscopic samples,
these granular samples exhibit unusually large saturation fields and MR
amplitudes. In addition, the evolution of the magnetoresistance curve as the
intergrain distance decreases is qualitatively different than that of large
samples. We discuss these results and suggest that they reflect a transition
from percolation to quasi single-channel dominated transport.
