Predictive Experiments on Neuroscience of Free Will
There is a good article on Wikipedia on the Neuroscience of Free Will, with far too much content to adequately summarize here.  Since your question is focused on long-term prediction of behaviour, I'll just mention about that.

Using newer fMRI technology, Soon et al (2008) used a learning algorithm to predict "free will" decisions from brain activity about 7 seconds (and up to 10 seconds) prior to the subject reporting awareness of having made the decision.  This experiment has been replicated in other labs: Presenter Marcus du Satoy undergoes it for the BBC documentary The Secret You (2009/2010), and remarks that there is something creepy about the radiologist being aware of his decision several seconds before even he is.



An important question remains regarding all long-term prediction experiments: Human behaviour is very predictable, as countless experiments in every area of psychology commonly demonstrate by manipulating causal factors - the ability to predict it well in advance with significant accuracy is hardly limited to neuroscience.  So experiments have to be very carefully designed if they are to eliminate the effects of predisposing factors such as priming in decision-making, such that decisions are not influenced by uncontrolled unconscious factors (hence truly "free will").  However, if "free will" doesn't exist, then eliminating all predisposing factors will ultimately prove futile, so until researchers can control for all variables, some doubt will always remain.

Nonetheless, research in this field has significantly changed our understanding of the role of "thought" or "will" or "volition" in the causal chain, such that they now appear to be a side-effect rather than cause of physical action.