Stickhorse, I'm not Brock but hope I can answer your questions.
The best two websites to find PPs and general info are:
www.racingpost.com
www.attheraces.com
Both of them require you to be a member, but signing up is easy and completely free.
Attheraces is a great website, packed full of facts and figures and free videos of past performances, and a lot of good people giving their thoughts. During Royal Ascot, I imagine there will be a micro site (might already be up).
The term 'NAP' I believe is a very old term and has something to do with Napoleon. Anyway, a 'NAP' is your best bet. The same as a 'Lock' which is what I gather the Americans call their best bet, am I correct?