Somehow I'm on TechRepublic's mailing list.  A blog entry lists the top 140 tech experts on Twitter. There seemed to be a lot of Americans there, so I thought I'd find out.
                                    
                                        - 1.  Extract the list from the blog HTML and cache in the database
- 2.  Parse the entries in the list, and for each:
                                        - 2.1 Use the twitter address to fetch the home page (at 01:00 UTC on 9th March)
 2.2 Parse the page to get the location and numbers of followers and following .
 2.3 Use Google Geocoder API to convert the location to lat / long
 2.4 Store in the database
Yep, all but 3 in the USA
                                    Only UK name I recognise : Jack Schofield (#100)
                                    Guy Kawasaki follows the most (240,262)
                                    Pete Cashmore is most followed (1,972,609)