Yahoo's launched Alpha (beta version), a multi-search tool that submits your query to multiple sources and aggregates results from all of them on one page.
By default, Yahoo web search results appear on the left, with drop down boxes on the right providing access to Flickr photos, Yahoo Answers, YouTube, Yahoo News, Wikipedia and Yahoo Sponsored results. You can remove any of these, or add any additional source (thus the customized comparison) provided it has an RSS feed. You can also easily change the layout of your Alpha page.
Source:→ SELYahoo!, Yahoo Search, Yahoo! Alpha, Beta