Microsoft (NASDAQ: MSFT) and Yahoo (NASDAQ: YHOO) announced in late August that the integration of the software giant's back-end search engine with Yahoo's sites was complete, after beginning that work only a week earlier.

"This week, Yahoo advertisers can begin transitioning their paid search campaigns to Microsoft adCenter. During the transition, which is on-track for completion by the end of October, advertisers will continue to manage separate accounts on adCenter (serving ads on Bing) and Yahoo Search Marketing (serving ads on Yahoo! Search)," David Pann, general manager of the Microsoft Advertising Search Network," said in a post to the Microsoft adCenter Blog Tuesday.

"Once the transition is completed, advertisers will operate one single account on Microsoft adCenter that will power search advertising campaigns across Bing and Yahoo's combined audience representing 31.6 percent of U.S. search market share," Pann added.

The announcement confirms the move to adCenter is on track to be in place by the end of October, although the companies still reserve the right to put off the transition until early next year should last minute problems arise.

"While we are confident that the preparation work done to date and the transition plan we are moving forward with now will help us reach this goal, please remember that deferring the paid search transition to 2011 is still a possibility if we conclude it would improve the overall experience," said a post on the Yahoo Advertising Blog.

The companies said in their blog posts that when the transition is complete advertisers will be able to target some 159 million searchers in the U.S. and another 15 million in Canada.

Additionally, in order to make the transition go smoothly, the two companies' blog posts explain the steps that paid search advertisers on both services need to go through. For instance, Yahoo account managers will be available to help Yahoo search advertisers make the jump.

In July 2009, Microsoft and Yahoo announced they had reached a deal whereby Yahoo will switch search features on its sites to use Microsoft's Bing technology in return for a share of the advertising revenue from those sites. The move to Bing to provide search under the covers was completed at the end of August 2010.

Microsoft's deal with Yahoo is scheduled to last for ten years. U.S. regulators signed off on the deal last winter.

Stuart J. Johnston is a contributing writer at InternetNews.com, the news service of Internet.com, the network for technology professionals. Follow him on Twitter @stuartj1000.

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