After making some rumblings this past March, Microsoft has now officially joined the iPhone development community with Seadragon Mobile, a free app that lets you "infinite zoom" gigapixel-sized images. Although Seadragon is a Silverlight application on the desktop, Microsoft isn't bringing Silverlight to the iPhone, so don't get your hopes up -- this is probably just some AJAX magic. We're itching to see if the company has any more apps in the pipeline -- wish for an Office editor but expect a Minesweeper variant.[Thanks, Mikkel]Filed under: