Ask YC: Grabbing content

First of all I would like to thank some of you who offered some life saving advice for my previous question.

Now that we have pulled up our socks and are making some headway, we have run into our first content problem.

We are building a business listings directory for a niche market. We have identified a bunch of ad-hoc sources for sourcing content. We have manually gathered content for our mockup, but to take it to the next level we need a lot more content than what we have going.

What are the different techniques used to gather content? It would be great if some of you have had specific experience in gathering content for some kind of a business listings directory.

Looking forward to some valuable insight!

Thanks again!