The most famous and successful search engine is Google but there are many others out there.
Google - This is the most popular search engine and provides the most successful pay for placement scheme adwords. You can submit your site here.
Overture - This is the paid placement service for MSN Search, Yahoo, AltaVista and many others. The search engines have their own spiders but use the same paid placement system.
MSN Search
- Microsoft owned and envious of the position held by Google. Keen to
improve their status and embark on TV advertising. Use Overture for
paid placement but their own MSNBot to search and index the web. You
can submit your site here
Yahoo - Both a directory and a search engine. Overture will be re-branded to use the Yahoo name shortly. Submit your site to the Yahoo search engine here and
to the directories by choosing a category that you want to be added to
then clicking submit site next to the search boxes on the page.