Rod Machado's Private Pilot Handbook is quite an easy read, it's mainly for PPL students but could be quite a useful reference for a more experienced pilot.
The Pilot's Radio Communications Handbook (author Paul Illman) is a good RT guide. RT over here is pretty straight foward, but there are differencies that may confuse.
Read up on CTAF, AWOS, US Airspace Categories, MOA, TFRs (
FAA TFRs), Flight Following, 1-800-WXBRIEF, DUATS & DUAT, Skyvector.com, Airnav.com.
If you have any specific questions on specific situations let me know.