Welcome to our forum.
I think "Polyamory: the new love without limits" (by Deborah Anapol) is a good book; also "Sex At Dawn" (by Christopher Ryan and Cacilda Jetha) comes highly recommended.
Also you can find Book and Website Recommendations at ... http://www.polyamory.com/forum/showthread.php?t=1096
"Ethical Slut" and "Opening Up" are like the top two major book titles, so you have a good foundation.
A few other staples:
Polyamory in movies/music/art? ... http://www.polyamory.com/forum/showthread.php?t=733
Golden Nuggets ... http://www.polyamory.com/forum/forumdisplay.php?f=26
Have a look at those three links, and browse around on the site, you will find a lot of good information.