Most are not exclusive to Web design but offer a variety of project categories. All, however, have projects for Web designers. A word of caution before you begin. You've probably heard the saying, buyer beware. In the Web world, there should also be a saying, seller beware.
Nothing is much easier to steal than a Web site.
Before beginning work on a project, take time to research the buyer. Even if they seem legitimate, a contract is a sound idea. Now, hang up the phone. Can also view other bids. Good search capabilities for locating specific types of projects.