In an international office like ours, the right tools are very important. My most important tool is the phone; I spend most of the day talking on the phone. All other important tools are electronic ones, as you can see from this screenshot (click for a larger version):
I e-mail a lot and use instant messaging through Trillian (MSN, AIM, ICQ, Yahoo and IRC in one application). But the handiest tool I have is the big image on the background: xearth for Windows. It shows me in a single screen which of our foreign contacts is awake. ;-)