OpenStreetMap is growing, with the likes of FourSquare switching to the service from Google Maps and Apple opting to use it for iPhoto on iOS. And from the looks of it, Microsoft's support might just be a key reason for this success. Bing has been using the open-source mapping tool since 2010, at which point Microsoft announced that it would be providing access to Bing Aerial Imagery to help move the project along. And in addition to providing information, PC World is reporting that Microsoft has also invested "big dollars" into OpenStreetMap. This all makes it appear as though Microsoft is trying to help build a solid competitor to Google Maps. And with more and more companies making the switch, it looks like it' could be on its way to doing just that.