I had a business with a "talker" once. I would not recommend doing anything together with such a person.
It was the place and time where I learned that words are cheap and I should always look at what a person actually DOES to see the truth about them. I learned to see facts behind the talk and it has helped me a great deal since then.
What I would do in such a situation: I would express sincere and honest interest about the project and then forget about it until the other person does or does not his job. If he never does it, I will not have wasted my time in empty anticipation, if he does - well, a great surprise for me!
I would never plan my life around empty words. There is always a time to reschedule if his words turn into works, but until then there are plenty of other exciting opportunities to go around.