Man,more toxic spam on this site,my gosh... My virus watch went off for every link that was suggested here.
You can buy a spot on Yahoo for 1 Year, it will help your rankings alot and will affect your position in other search engines as well.
But Bing and Yahoo make a pretty good team,so I think doing SEO for both search engines(Bing does them both now) could give Google a kick in the teeth now.
help.yahoo.com/l/us/yahoo/smallbusiness/webhosting/promote/promote-07 <-here you can see details to promote your website.
Yahoo directory is one of the best way to promote yahoo search engine. You can try to do this method.
Submit your site to Yahoo Directory & add the Yahoo Site Map http://help.yahoo.com/l/us/yahoo/smallbusiness/store/promote/sitemap/sitemap-06.html Other promotion strategies are same as Google.
if you need to promote your site in yahoo.. go for lots of backlinks.. yahoo love bcaklinks.. where as google love quality backlinks..i was on frist position in yahoo in just 1 month when i created more than 10K backlinks in a month.. ofcourse google sandboxed me