Search engine registration is the quickest method for getting your site listed on public engines. Many search engines claim that only the root page of a site needs to be submitted and all pages will be spidered automatically. However many times the spidering may take months or never happen at all. For some search engines it is best to submit every page you want indexed.
Some search engines have limits to the number of pages that can be submitted from a single domain.
Many search engines will drop some or all of your pages after a time. Make sure to monitor whether your pages are currently indexed and resubmit any that have fallen out of the search engine.