See the original videos here: http://www.teachingenglish.org.uk/article/video-interviews-david-crystal
I couldn’t add the videos from that site to here, but now British Council Russia have added them, making them more accessible.
A couple of sites with more about David Crystal.
His homepage, where you can buy his books and see where he will be presenting: http://www.davidcrystal.com/home
And his blog, with some interesting posts: http://david-crystal.blogspot.com