There's a review article in this week's Science (v.320, April 4 2008, 65-68) that is potentially of philosophical interest, "Stochasticity and Cell Fate". The bumper sticker version: although a cell's transformation into a specialized subtype is deterministic in most cases, "[i]n some cases, however, and in organisms ranging from bacteria to humans, cells choose one or another pathway of differentiation stochastically, without apparent regard to environment or history."
Discussions of indeterminism in biology have usually been restricted to the 'random' mutations that drive evolutionary change. This, if it holds up, looks to be a quite different kind. And interestingly, the authors point out reasons why a certain degree of indeterminism may confer selective advantage upon organisms whose development contains stochastic elements.