I tested the waters some by submitting to a site called www.mopilot.com
You will get your site listed immediately and should start pulling in around 5-10 hits average per day depending on the keywords. Decreases with time due to others submitting their stuff as well. Similar to how NBCi's live directory works.
Like Mike said the market is pretty thin but you will find a lot of users out their visiting the pages if you can find the various search engines for it.
If you don't want to go through the trouble of setting up a few "decks" or "cards", aka sites or pages, then just create one page. Throw your domain name up there with a brief description. Maybe ask them to visit the site when they get onto a PC. Pretty good way to brand your products, services, or domain name.