The SilentSync interface is minimalistic. It is built on top of the Microsoft .NET framework, and styles itself according to the platform it is run on. Here is a screenshot:

Silent Sync is licensed under the GNU General Public License
Silent Sync and this website are copyright © 2007–2008 by Rico Huijbers
I will not put my e-mail address here, but if you want to contact me, you can leave a note on SilentSync's SourceForge support request tracker.