A KVM switch (Keyboard-Video-Mouse) is a major boon to anyone who has to work with more than one computer. You can change computers without having to give up the keyboard and monitor you're already using, sometimes via the keyboard itself. Imagine the space and money you'll save, only having to buy one monitor, keyboard, and mouse.
After saying that, KVM switches stop being exciting pretty quickly, so let's look at things to shop for. Will it switch your speakers, too? How about your microphone? Is it USB only, or can it handle older connections? Hardware button, keyboard command control, or both? Does it draw its power from the computer, or does it need a power adapter? How many computers do you need to switch? (Most KVM switches will handle two computers; some can handle more.)
The TRENDNET TK-408K is a 4-port PS/2 KVM switch that lets you manage four PCs with just one set of keyboard, monitor and mouse. It comes with a set of MIC/Speaker port so you can also share microphone and speakers. PC selection is easy via the push button or hot-key commands. With the hot-plug feature, add or remove PCs without powering down the KVM switch or PCs. Is this the switch for you? Check it out and see!