Directory Submit -
In commercial categories, Yahoo requires that sites pay a Yahoo Express submission fee of $300 (well, $299) per year. This fee doesn't guarantee that you will be listed, only that you'll get a yes or no answer about being accepted within seven business days. However, the vast majority of most decent sites are accepted. There is no guarantee regarding ranking, only that you will be put into the Yahoo! Directory, so properly optimizing your site for search engines is still critical.
If accepted, you'll be reevaluated after a year and charged the submission fee again, if you want to stay in Yahoo's commercial area. You should review the traffic you received from Yahoo over the past year, to decide if it is worth paying the fee again. If not, you can decline to be listed, and you will not be charged. Usually you will stay in the listings anyway if you have built up a good links program.
Go to http://add.yahoo.com/fast/add?+Business to learn more.
Search Submit -
Yahoo! also has an option called Search Submit which guarantees inclusion into the search database of several search engines. You must pay a fee for each web page you submit, and then you pay a "per click" fee for each time someone clicks on the link to one of your web pages.
Go to http://searchmarketing.yahoo.com/srchsb/index.php to learn more.
Sponsored Search -
In order to get your website in the top of the search engine results, another option is Sponsored Search. These are ads that you see at the top of the search pages in Yahoo and several other related search engines. The cost can be quite high if you are in a competitive area.
To learn more about sponsored search, go to http://searchmarketing.yahoo.com/srch/index.php