The ODP (http://www.dmoz.org/) is organized into categories and subcategories, and as simple as it may sound, the key to submitting is finding out where your site should be listed. There are two good ways to determine where your site belongs. You can perform a keyword search, then "drill down" to find the category that sites returned by the search belong to, or you can manually find the right category by drilling down from the home page. I would recommend manually finding the right category, because some sites returned as search results may not belong to exactly the same category your site should be submitted to.
For the sake of illustration, let's say you run a for-profit, defensive driving school, and I need to find the correct category to submit to. From the ODP home page, I would probably select the broad category of "Business", because after all, I am out to make a profit, so that seems like a pretty logical choice. The next page I'm presented with has around fifty subcategories. "Training and Schools" sounds right, so I'll choose that one. I'm then provided with the various categories of training schools, and "Traffic Schools" is among them, so I'll choose it. This is probably the category where I need my site to be listed, so I'll submit here.
The category selection process just described would apply to any site, and the more specific the category you submit to, the more targeted your traffic will be. After finding the right category to submit to, click the "add URL" link at the top of the page that the category is presented on. The add URL page has three mandatory fields and one optional field to fill out in order to submit a site. The first field is the "Site URL" field, and the site's URL should be entered here exactly as it will appear in the directory. The second field is the "Title of Site" field. For this field, your company or organization name should most likely be used, but if possible try to throw in a keyword or two. For example, if the name of my hypothetical business above is "No More Tickets", I would do well to add the phrase, "Defensive Driving School" to the end of it. The reason for this is that search results for the ODP are based on keywords in the title and description (and to a certain extent in the URL, e.g. http://www.keyword-keyword-keyword.com/). With this in mind, try to add some keywords when filling out the last field as well, "Site Description".
The site review and addition process can take anywhere from several weeks to several months, depending on the amount of submissions to that category and the category editor's responsiveness. It is slow process, but it's definitely worth the wait if you get a listing in the ODP.
About the Author
Alan is the lead developer for InfoServe Media, LLC (http://www.infoservemedia.com/), a Web development company that specializes in Web site design, hosting, domain name registration, and promotion for small businesses.