Clipboard Sharer lets you share a common logical clipboard between two machines on Linux, OS X, and Windows.
I plan on adding new features as I need them. Currently it only supports text, but files will surely come soon. Also, if someone requests it, I'll change the 1-1 relationship to 1-N (meaning you can connect any number of machines). A history tool will also be added soon, allowing you to fetch older clipboard elements.
Note: The binaries will require the Qt Runtime which can be found at http://qt.nokia.com/downloads.