I noticed a couple tweets floating around today about leaked images of UI in an upcoming version of Microsoft Outlook that mimics the Windows Phone 7 “Metro” UI style:

Office 15 Outlook

Also, keep in mind the demos of the upcoming OS X Lion that Apple’s been showing off (the Launchbar feature is shown here, which looks the same as folders on iOS):

OS X Lion

It’s interesting to see desktop OSes taking major cues from mobile UIs.