  The entrainment transition of coupled random frequency oscillators is
revisited. The Kuramoto model (global coupling) is shown to exhibit unusual
sample-dependent finite size effects leading to a correlation size exponent
$\bar\nu=5/2$. Simulations of locally coupled oscillators in $d$-dimensions
reveal two types of frequency entrainment: mean-field behavior at $d>4$, and
aggregation of compact synchronized domains in three and four dimensions. In
the latter case, scaling arguments yield a correlation length exponent
$\nu=2/(d-2)$, in good agreement with numerical results.
