Well, here's something of a surprise -- Microsoft has just brought its OneNote app to the iPhone, and it's made it available as a free download "for a limited time" to boot. As with the Windows Phone 7 app (previously the only mobile version), the iPhone app will let you manage notes and shopping lists (and even add pictures taken with the iPhone's camera), and then sync those with Windows Live SkyDrive so you can access them in either the Windows desktop application or its web-based counterpart. As ZDNet's Mary Jo Foley notes, however, perhaps just as interesting as the app itself is the question of what else might follow -- a native OneNote app for iPad, perhaps, or even iOS versions of other Office applications? Microsoft unsurprisingly isn't commenting on those possibilities, but it did note that the OneNote app is the culmination of some 18 to 24 months of development from a team of Microsoft Mac Office and OneNote engineers, which is either a sign of some serious slacking or a fairly significant commitment on Microsoft's part. No word on when the "limited" free period will run out (so you'll probably want to grab it while you can), nor is there any world on a worldwide release -- it's currently only available to US users, unfortunately.[Thanks, Pradeep]