I realise that TalkingHorses has a band of experts on board, but many of us have a few holes here and there in our racing knowledge, and there are sometimes questions raised which even our experts aren't sure about. I don't know if the BHA website has been put up before, so, apologies if I'm just repeating it, but it is very useful and informative, giving a lot of insights into the whys and wherefores of its function. Plus, you can always contact it if you have a question the forum can't handle.
http://www.britishhorseracing.com/inside_horseracing/about/default.asp
http://www.britishhorseracing.com/inside_horseracing/about/default.asp