Not to say that quantum randomness really counts as "free will" either. I'm not exactly sure how you would define it.
Researchers keep finding more ways that life uses quantum physics, including photosynthesis, the avian compass, and (maybe) the sense of smell:
http://www.youtube.com/watch?v=wcXSpXyZVuY
http://www.bbc.co.uk/news/science-environment-12827893
So it wouldn't be all that surprising if they find quantum tricks in the brain, too.
Aside from that, there's radioactivity in your body, including your brain. I saw a speculation once that radioactive decay sparks electrical signals in the brain, which the brain sometimes amplifies enough to change macroscopic behavior. If that's the case, that would prevent our actions from being deterministic.