Microsoft is targeting the iPhone as another avenue for boosting usage of its Bing search engine.
On Thursday, Microsoft released a software developer kit designed to make it easier for iPhone developers to build access to Bing into their applications.
Using the SDK, a developer can build an iPhone application that searches Bing for Web information, images, videos, news and phonebook results.
Developers can only query Bing from applications built on Cocoa or Cocoa Touch, APIs (application programming interfaces) for building applications on the iPhone.
Google is the default search engine in the iPhone's Safari browser, and users can decide to switch that to Yahoo.
Otherwise, if iPhone users want to access Bing today they have to type in the URL.
The SDK will also let developers incorporate Bing searches into applications for Macintosh computers.
While Microsoft and Apple compete in the mobile-phone market, other Microsoft services and applications are already available on the iPhone.
For instance, the iPhone supports Microsoft's ActiveSync to let people access their Exchange e-mail.
In addition, Microsoft's Live Labs group released an iPhone application for Seadragon, the technology that lets users browse through potentially very large images.