Apple and Microsoft are in talks to replace Google as the default search engine on the iPhone with Bing, “Apple and Google know the other is their primary enemy,” says one of the people, who’s familiar with Apple’s thinking. “Microsoft is now a pawn in that battle.” Apple is also working on ways to manage ad placement on its mobile devices, a move that would encroach on Google’s ad-serving business, the person says. “A deal between Apple and Microsoft may mean iPhone owners would automatically get Microsoft’s Bing as the main search engine, possibly requiring users to actively change phone settings if they want to search via Google. Google is now the default search engine on iPhone. To search via Bing, a user needs to download a Bing application or go through browser to call up www.bing.com. Microsoft may also be lobbying to make Bing an alternative on Apple’s Safari browser for Mac users. Currently, Mac users can choose either Google or Yahoo search through the Safari browser,” Business Week reports.