Microsoft, in cooperation with Federated Media and Twitter, launched its own Twitter search engine today. BingTweets mashes up real-time Twitter search with results from Bing
BingTweets enables you to see deeper, real-time information about the hottest topics on Twitter by fusing Bing search results with the latest tweets. To get started, click on a trending topic, or search for anything that's on your mind in the search box below.
Check it out: http://bingtweets.com/