For the major search engines, if you get incoming links to your site from other quality sites, your site will be found. The best way to be sure your site is found is by submitting to the major directories that are crawled by the search engines. This is a good approach for the search engines to take because sites listed in directories have already been reviewed by an editor and been considered to be worth a listing.
So, in addition to the traffic that the directories can send to your site directly, getting listed in the major directories is also important for getting your site found by the major search engines.
To get started, be sure to get your site listed in the following directories that are crawled by the search engines. Your site can be submitted to these directories for free (some may require you to become an editor first):
Open Directory Project <http://www.dmoz.org/> - Also known as ODP or DMOZ.
When you are submitting to directories, be sure to take the time to find the best category for your site and read the submission guidelines provided by each directory. By following their guidelines, you will improve your chances of being listed and decrease the amount of time it takes to get listed.
Obviously, there are many more directories where you can submit your site. These three are provided to get you started. After you've submitted to these directories, then you can begin submitting to other directories. Don't forget to find local or thematic directories that are relevant to the topic of your site. <http://www.searchengineguide.com/searchengines.html> and directories.
It will take time for the search engines to index your site after it has been listed in the major directories. So, be patient and expect to wait at least a couple more months before your site starts appearing in the index of the major search engines.