DMOZ The Open Directory Project
In their own words: “The Open Directory Project is the largest, most comprehensive human-edited directory of the Web. It is constructed and maintained by a vast, global community of volunteer editors.”
The DMOZ human-edited review process assures that website's in the directory are actually about what they say they are about. Their selective process keeps the directory more concise and higher quality than most search engines. Further, the DMOZ directory listings are actually used by hundreds of commercial search engines including AltaVista, A9, AOL, Clusty, Gigablast, Google, Lycos, MSN, Teoma and Yahoo.
Getting Listed in DMOZ
Drill down to find the category where you should be listed. On that page, find the link in the upper right hand corner for "suggest URL". Fill out the information and submit.
Read through their information on the submittal process. You my find that you need to follow up more than a few times. Keep in mind that it is all run by people that volunteer their efforts.
Getting Listed in more than one category
Depending on your business you may be able to get listed in a general category and a specific geographic category. If you find more than one applicable category then you can submit again. As a rule, DMOZ editors share information and try to limit most websites to the single most appropriate category.