Chapter 26: Ludwig Wittgenstein
A thorough, though brief, discussion of the early and later Wittgenstein can be found at http://plato.stanford.edu/entries/wittgenstein/
The first hundred sections of Wittgenstein's Philosophical Investigations, together with a commentary, can be found at
http://users.rcn.com/rathbone/lwtocc.htm
A YouTube interview with John Searle about Wittgenstein (in several sections) is available at http://www.youtube.com/watch?v=qrmPq8pzG9Q
A YouTube interview with A.J. Ayer about logical positivism can be found at http://www.youtube.com/watch?v=DMlXmLbGKJY