Public Domain Sources?

I know this is not EXACTLY what you are
looking for but thought it may help...

List of Free Content Locations

1. Google U.S. Government Search
Google has indexed U.S. federal, state and local information. It's probably the largest source for public domain content. <Unclesam> - Google Search

2. Project Gutenberg
It is the oldest digital library. Most of the items in its collection are the full texts of public domain books. The project tries to make these as free as possible, in long-lasting, open formats that can be used on almost any computer. As of December 2007, Project Gutenberg claimed over 24,000 items in its collection.
Main Page - Gutenberg

3. Amazon.com
Join their affiliate program and you'll have instant access to all their content. You can use all their reviews, descriptions etc to link to their products. You can create sites instantly using scripts like the Amazon Products Feed [http://www.mrrat.com/aws/] Amazon.com: Online Shopping for Electronics, Apparel, Computers, Books, DVDs & more

4. Article Directories
These are directories that contain thousands of articles which you can republish on your site. Most popular are: EzineArticles Submission - Submit Your Best Quality Original Articles For Massive Exposure, Ezine Publishers Get 25 Free Article Reprints, Article Search Engine Directory: GoArticles.com and ArticleCity.com - Free Articles for Reprint. Free Articles for your web site and newsletters. Submit Your Articles to Our Articles Directory.

5. Wikipedia - the free encyclopedia
Contains over 1,074,006 encyclopedia style articles in English that you can use on your site. "All of the information in Wikipedia is free for anyone to copy, modify for their own purposes, and redistribute or use as they see fit, as long as the new version grants the same freedoms to others and acknowledges the authors of the Wikipedia article used (a credit or backlink to the original article is sufficient for this)." Wikipedia, the free encyclopedia & http://www.internet-encyclopedia.org/

6. Affiliate Data Feeds.
You can create entire sites using these data feeds. Just join an affiliate program and you'll get access to these feeds. You can create sites in minutes using Affiliate Datafeed Processing Tools - FeedProcessor.com. Data feeds are available from some merchants on Affiliate networks like Commission Junction, Performics, Linkshare, Affiliate Window. Affiliate Window has the most comprehensive free affiliate datafeeds. Using Affiliate Window and Feedprocessor.com you can crank out hundreds of sites in a few weeks. For more Affiliate Datafeeds check out the AbestWeb Marketing Forum.

7. RSS Feeds
These are a great source of free content and they are everywhere on the web. Use free software like Wordpress: WordPress › Blog Tool and Publishing Platform and FeedWordPress: http://projects.radgeek.com/feedwordpress to create a blog and post entries automatically. e.g: Yahoo! News Search Results for KEYWORD for news feeds or http://www.freerssfeeds.org/amazonus...ywords=KEYWORD for Amazon product feeds.

8. PRWEB
Searchable database of thousands of Press Releases that you can publish on your site. Search Press Releases - PRWeb Newspad

9. The Cranky Librarian
Search for public domain books and art works online here, as well as searching by author and artist. Cranky Librarian

10. The EServer's Fiction collection
This site offers works of and about fiction collected from our members, contributing authors worldwide, and texts in the public domain. Fiction: Welcome to The EServer's Fiction Collection

11. World Wide School
Educational material- The library contains over 2,000 online texts organized by subject, author, title, and genre. http://www.worldwideschool.org/library/

12. Copyright Free Photos
Probably the largest collection online. stock.xchng - the leading free stock photography site

Not sure what your asking exactly.
Are you looking to determine if a certain book is in the public domain
or are you looking for books that are public domain.

Either way here is a handful of resources that I have used from time to time.

Authorama - Public Domain Books

Page By Page Books. Read Classic Books Online, Free.

ManyBooks.net - Free eBooks for your PDA, iPhone, or eBook Reader

Public Domain Works - Home

Google Books

I also have a free report located in the make money section of the Warrior Forum that may help you out, no opt in required. Here is the link to that ebook,
http://www.warriorforum.com/make-mon...-required.html

or you can checkout the WSO in my sig which provides over 300 Public domain resources from a variety of categories.

Hope that helps.

I actually thought he meant PLR articles, this is almost impossible for me to find without people trying to get you to pay for it...

Does anyone has a repository of FREE plr please or is this an entirely mythological and non-existant beast?