Apostolos Suos 
Apostolic Letter on the Theological and Juridical Nature of Episcopal Conferences, issued motu proprio by John Paul II, 1998.
http://www.cin.org/jp2/apost.htmlEpiscopal Conferences: Historical, Canonical and Theological Studies
1989 book, full text online. Scholarly essays by several authors.
http://www.georgetown.edu/centers/woodstock/reese/ec/ec-content.htm
"Episcopal Conferences" in the Catechism of the Catholic Church
Paragraph 887 of the CCC mentions episcopal conferences. From this same page, you can put this paragraph in context by reading the surrounding section of the Catechism.
http://www.ziplink.net/cgi-bin/cgiwrap/kerygma/a.pl?k=%22Episcopal+Conferences%22&b=C&t=and
Episcopal Conferences
Section on bishops' conferences in the 1983 Code of Canon Law.
http://www.intratext.com/IXT/ENG0017/_P1W.HTM
