I believe very strongly that free will is tied to the existence of randomness. Without randomness there can be no free will.

From the little I've read it appears that true randomness does exist, in that there are experiments where all causally relevant variables are controlled and yet the outcome is still uncertain.

I'm not convinced that there is true randomness in the universe however, and I guess that means I subscribe to some sort of hidden variable theory with regards to the aforementioned experiments.