I'm curious: what is the silver round knob-like device next to your mouse? I saw it in a store that specialized in selling used Macs in Osaka, but when I tried to fiddle with it, it became clear I either didn't have the right program open, or it wasn't properly connected; it didn't do anything.
What does it do?
It is a Griffin Powermate (http://www.griffintechnology.com) that is customizable to do many functions. For example in Firefox turning the know left or right scrolls up and down. Pressing the knob down while scrolling left or right goes Back and Forward in the browser. In Finder it acts as a volume knob. In iTunes it acts as volume/play-pause (with a click), seek fwd/back (press + rotate). Using the powermate in Entourage when i rotate left and right it scrolls, when I press down it sends/receives email. It also can function as a jog wheel in Final Cut/iMovie. Its really just an all around nice tool to have. like I said, fully customizable in system prefs.