Clipper 0.1 released
Clipper is an OS X "launch agent" that runs in the background providing a service that exposes the local clipboard to tmux sessions and other processes running both locally and remotely.
A binary download (for OS X 10.8 Mountain Lion) can be found on the Clipper product page.
For more details, see the 0.1 README.
Update: I’ve added a screencast to the Clipper product page demonstrating what it can do.