This site contains 160 pages of Spitfire pilots, their squadrons and when possible, the codes and serial numbers. It also contains, with permission, the data from The Spitfire Production site so the is two sites in one This section contains 1530 pages...

http://allspitfirepilots.org/index.php

For those who haven't heard of the Spitfire Production site, it is attempting to list every Spitfire/Seafire built along with a brief history where possible...

http://www.airhistory.org.uk/spitfire/home.html