There is no absolute free will. But we have a will (intention). The mind is like a random thought machine. Initial thoughts are triggered by our senses (for example; eye and object) are modified by our memories (see the post on cognitive series). Our likes, dislikes (feelings) and perceptions will modify our subsequent thought process (see the post on how the mind works). There is no self or a person in control of all these (see the post on the anatomy of a being). These are just the activities of the five aggregates (see the post on five aggregates). This creates a false sense of a self in control (see the post on personality view). This is just a process and therefore free will is not possible. There is now some scientific evidence* supporting this.
How about determinism? Everything does not depend on our Kamma (see the post on kamma). Kamma can be modified or extinguished (also see the post on how kamma works). There is no evidence that a God** is in control of our destiny either.
So we are deluded form the reality. The greed, hatred, delusion (ignorance) and fear put us off the tack from the path to awakening. The awaken one knows there is no self. This is just the work of the five aggregates. That's all. He knows that there is no self, no being or an external source in charge of him. He is fully mindful of all the thoughts as they arise and does not cling to a idea of permanent self. He knows for himself there is no permeant self by his own experience of internal investigation of the mind. He has the direct knowledge of the truth. This is the insight he gains through the practice of mindfulness meditation. There is no more ignorance, craving or even clinging. He is totally free and liberated within. There is no more birth for him.
** Related Discussions/Sutta:
1. "Buddhism and the God-idea", by Nyanaponika Thera. http://www.accesstoinsight.org/lib/authors/nyanaponika/godidea.html . Retrieved on 24 November 2011, 7 June 2010,
2. "Tittha Sutta: Sectarians" (AN 3.61), translated from the Pali by Thanissaro Bhikkhu. http://www.accesstoinsight.org/tipitaka/an/an03/an03.061.than.html . Retrieved on 24 November 2011, 3 July 2010,.
3. Tevijja Sutta (DN 13): Page 9-21 and 78-91; Basic Teachings of the Buddha by Glenn Wallis, 2007, Modern Library, NY
* Related links: