I've always been certain Szabo is Satoshi but even more convinced after hearing the pod-cast. He seems to go out of his way to refer to Satoshi in the third person. Also the fact that no-one really knows much about Szabo shows that here is an individual who is very careful about protecting his identity. I think also that Andreas knows that he is Satoshi - he's almost referential is his questions to Szabo.
So little is known about Szabo. How did Let's Talk Bitcoin know it really was Szabo they were talking to? I tried finding out more about him and kept hitting brick walls. I found about two very old pictures that may or may not have been Szabo. There were differences of opinion about where he used to work and what his qualifications were. His identity is almost as secret as Satoshi's.