Note: This review addresses v1.3.1 of the software.
If, like me, you have multiple PCs with different operating systems running side-by-side on your desk, you're probably tired of all those keyboards and mice cluttering up your workspace. With a freebie called Synergy, you can kiss most of those input devices goodbye and use the keyboard and mouse from one PC to control the machines around it, even across platforms. So you can work on your Windows PC, point the mouse cursor off the edge of the screen, and watch it appear on your Mac or Linux box as your keyboard and mouse take control of the new machine. On my desk, Synergy is controlling all three of my systems--running Vista, Leopard, and Ubuntu. A Mac version is available as well.
Note: This program is donationware. It is free to try, but the authors accept and encourage donations towards further development. This link takes you to the vendor's site, where you can download the latest version of the software.