Any Internet marketer will tell you that the public domain is a goldmine. But if you've only been making money on ebay, you might not know how to cash in this goldmine.

The "public domain" is the collection of all documents that are publicly-owned. This usually includes really old documents and books, government documents and information, and documents created specifically for the public domain.

There are thousands and thousands of documents currently in the public domain, many of which are easily accessible over the Internet.

Before you can cash in on this goldmine, you must first find a product people are actively searching for on ebay. It could be information about building computers; it could be information about curing acne; it could be information about breeding dogs. There are dozens of possibilities.

Once you have determined what type of product you want to create and sell on ebay, you should start trying to put together some public domain information for your product.

Let's say you selected "dog breeding" for your product. You can start compiling information and pictures by searching for "dog breeding" on wikipedia.org and wikimedia.org. If the pictures and information you pull up fall into the "public domain," then save them in a folder on your computer.

Next, search Google for publicly-owned "dog breeding"sites and government sites that have information about dog breeding. Add all of the information you find to the same folder.

Organize all of this information logically and put it into a single word-processing document.

Now go to www.pdf995.com, download the trial version, and use it to compile your public domain product in PDF format.

Your next step is to take this public domain product and make money on ebay selling it. This is pretty simple. If you found a good market niche, you should have no problem making money on ebay.

Sell the product as you would normally sell anything on ebay. Remember to pack your auction title and description with highly-trafficked, related keywords. Include a picture and long description for your PDF "ebook."

Whenever someone purchases your product, you can simply email them an attached file with your product.

If you want to minimize the amount of work you have to do, you can automate the download process by setting up a custom check-out with paypal that redirects your customers to a download page on your website (if you own one). If you don't own a website, you can upload the file to a free geocities.com account and direct your buyers there.

You now will have a completely automated sales machine that will constantly make money on ebay. All you have to do is setup the auctions--and your machine will do the rest.