In the latest sign that the iPhone is emerging as the platform of choice for companies of all sizes, Yahoo on Wednesday will reportedly cease work on its Mobile app for BlackBerry and other smartphones to concentrate its resources on iPhone and browser-centric development.

Word of the move was picked up by blog site TechCrunch after developers applying to work on the application for Research In Motion’s BlackBerry handsets received an email response from the search giant stating that “Yahoo has decided to cease development” of the app on May 20th.

Going forward, Yahoo will reportedly restructure its Yahoo! Mobile development team to focus on two core platforms, the iPhone, and for every other mobile handset, the browser. Other applications for BlackBerry handsets independent of the Mobile app will reportedly remain in development.

As TechCrunch points out, Yahoo’s move to abandon development of its Mobile app for BlackBerry and other smartphones is somewhat of an about-face for the internet company, further underscoring the impact the iPhone has had on the market in just a matter of months.