One piece of research I remember reading about a while ago was on the question of how deterministic or stereotyped an insects behaviour was. Their results suggested that the fly's behaviour was not simply a deterministic one with any behavioural variation being caused by environmental variations but rather that the brain itself produced spontaneous flight maneuvers in a structured non-random manner (
Maye et al., 2007).
Whether this is truly an example of the mechanism behind 'free will' and how it ties into consciousness is a very knotty problem.
Do more complex neural structures perhaps tend to produce more such spontaneous patterns and does the increasing complexity of these patterns and their interactions lead to what we experience as our continuing consciousness?
I'm sure Syamsu will be glad to hear science is taking more of an interest in 'free will' and decision.
TTFN,
WK