I do not have much in the way of reference info on the PIC at the moment but I do have some good links. I only present the best links so you do not have to waste too much time.
This is a good site for newcomers to the PIC.
There is a mailing list you can join, beware of the high traffic though. A lot of professionaldevelopers of the PIC are on this mailing, as well as a number of hobbyists, a great reource for PIC queries.
There is a FAQ, read before posting to the list.
There is some reference info here. An instruction set reference here.
The manufacturers of the PIC microcontroller. They have application notes, PC development tools and a whole lot more on their site. They encourage the hobbyist user, which has helped the PIC become number 2 in the 8 bit microcontroller market.
Can't find the proper site name but it does not matter. It has a large number of links to many things PIC related. From development tools to applications to consultants it contains a lot of info. It has not been updated since July 31st 1999, when I last checked, so some links are now invalid.
Updated 30 August 2010