3.Dropbox: Dropbox is a Web-based file hosting service operated by Dropbox, Inc. which uses cloud computing to enable users to store and share files and folders. <a href="http://www.dropbox.com/">http://www.dropbox.com/</a> 4.isynchr: I have more than 10,000 songs in itunes, but when I bought my android HTC phone, figured that would have to carry two devices.