For those of you who don't read Time Out, I thought I'd point you in the direction of an audio tour download which they produced in conjunction with Warner Brothers to promote the movie 'Sweeney Todd'. It's free, and you can put it on any MP3 player (or presumably stick it on a CD and play it on a Discman).
It's in the general vicinity of Fleet Street, and the download includes a map.
http://www.timeout.com/london/microsites/sweeney-todd/audiowalk/