I am considering taking a pub crawl in London with my 3 sons. Any recommendations?
Jeffrey. Look up London Walks, walks.com. They do 3 or 4 walks every evening including pub walks. Take two hours. Different themes. Should get you started.
We created our own pub crawls using the excellent http://fancyapint.com/ . I just clicked on the Borough location and saw that I could string together the 5 pint rated Royal Oak and Lord Clyde and continue to the 4 pint rated Kings Arms and Market Porter. Familiarize yourself with the website and see if you can't come up with some walks to call your own.
If your interested in seeing the more traditional and older pubs
check out the 2006 Timeout magazine list of pubs. Believe all of them are still working and haven't been bought out and made into wine bars.
Agree with Chip-check out fancyapint for pub ratings and arrange your own pub crawl.