For our logo design company (
http://fairpixels.co), we open source our unused logo designs on
http://logodust.com and make them available for free. We promote Logodust to bloggers/reporters and have gotten some publications on sites like TheNextWeb. A good chunk of those visitors then upgrade from the free logos to a paid, custom design. We have a pretty healthy and consistent flow of visitors to Logodust so paying clients knock on our doors consistently.