Finally Yahoo and Bing search alliance started from today ie 3rd August 2011. Yahoo announced that they are now ready to transition Yahoo! Organic Search Results (non-paid listings found on the main body of the Yahoo!) to Microsoft. The organic search transition will begins on August 3rd 2011 for Yahoo! European properties in the UK, France, Germany, Spain and Italy.
Following are the screenshots of search result of Yahoo UK and Bing UK for the same keyword "Data Recovery Software":-
You can see that the results are same in both the search engines. Now if you want to get better ranking on Yahoo then only optimize your site for Bing and you will automatically get the same ranking on Yahoo. So just Review the Bing webmaster tools and optimise your website for the Bing crawler, to help ensure your site is prominently listed in both Yahoo! and Bing organic search results.
Also note that Yahoo! is NOT transitioning paid search results at this time, and you should continue managing your Yahoo! Search Marketing account as usual.
For more information please visits the Official site at http://ebm.yahoo-email.com/c/tag/hBONmsVB8WDXMB8cj4cEGWsiOIp/doc.html