  I present results for two-loop soft anomalous dimensions for heavy quark
production which control soft-gluon resummation at
next-to-next-to-leading-logarithm (NNLL) accuracy. I derive an explicit
expression for the exact result and study it numerically for top quark
production via e+ e- -> t tbar, and I construct a surprisingly simple but very
accurate approximation. I show that the two-loop soft anomalous dimensions with
massive quarks display a simple proportionality relation to the one-loop result
only in the limit of vanishing quark mass. I also discuss the extension of the
calculation to single top and top pair production in hadron colliders.
