For serious syncers who routinely work from multiple computers or mobile phones, SugarSync is, in more ways than one, a premium solution to file-transferring problems. More flexible than some competing PC-to-PC syncing software or mobile and PC remote access services, Sugar Sync weaves in elements of both. Lite sync some folders for online back-up and fully sync folders or files to load them on each of your computers. A change to one file exacts a change to all.
SugarSync doesn't do everything, and the mobile functionality could use some usability finessing. There are also a few tricks worth knowing to ease your way. Here's a good one--if you're not interested in transferring every icon or EXE to all hooked-in computers, before syncing your Desktop folder, either move the elements you do want to a different folder and bypass the Desktop sync, or throw everything into a new folder on your desktop and exclude it from the syncing.
SugarSync managers are available for Windows, Mac, BlackBerry, Windows Mobile, and iPhone. A free trial of the service is available for 45 days. SugarSync premium storage prices can be found here.