I used to use Synergy on my Linux desktop and Mac laptop, to allow me to share the same keyboard and mouse between the two. After upgrading to a 64-bit Linux distro (FC12 btw), Synergy would no longer compile. Instead of trying to fix this, I went searching, and found Synergy+ instead. It works great on my boxes, and is even backwards compatible with Synergy. But best of all, it's actively maintained and supported, give it a try.
Now that I found it, I realized that it's even available in the Fedora Core distribution (yum install synergy-plus)