There's this website I found that has some pretty good info about PIC instructions:
http://www.mikroe.com/en/books/picbook/A_appendix.htm" onclick="window.open(this.href);return false;
This one has some pretty good basics and will help you get started with the basic examples it has:
http://www.mstracey.btinternet.co.uk/pi ... icmain.htm" onclick="window.open(this.href);return false;
I have a book called "Programming and Customizing the PIC Microcontroller" I think it's by Mike Predko.
If you wanna learn to program these, I highly recommend you get yourself a development kit as it's hard to understand what the heck is going on in the code unless you play with it for yourself.