I didn't really notice this till it was silent in my office but when I listened whenever I moused over the Dock or I moved the cursor to a hot spot or clicked any menu for that matter I can hear a faint short hum from my speakers now it's nothing severe but it's a slight hum as if you hummed in the back of your throat softly. Has anyone else noticed this strangeness? I am using the AC97 Apple Drivers. Hopefully I'm not crazy :P

The problem is your internal (speaker) buzzer. unplug it

Ya my internal is unplugged the humming stops when I turn off my speakers though : /.

Could be coming from the relationship between your monitor and your speakers. Is your monitor a CRT? What happens if you move your speakers away from your monitor? These suggestions are totally not related to Leopard of course, so maybe I should ask if you notice anything like this in Windows...?

My speakers are about 2 - 3 feet away from the monitor the humming only occurs when you interact with the desktop like cursor over the Dock doesn't occur just moving the mouse on a blank space, the cursor has to hit a trigger on the desktop.

in windows you can disable the internal speaker in sounds preferences (sound mixer) but i don´t know if it´s possible in mac.

Well like I said the internal speaker isn't connected in my computer I never did when I built it the sound is coming from my speakers connected to the AC97 Diver cause when I unplug them the sound disappears. Probably no fix for it just wanted to know if it was a common issue.

How do you listen the sounds of your bios at boot ?

I have not noticed this, but I have noticed that when installing leopard that weird sounds/noises are being
generated by my system through desktop speakers. Its like the install process is putting such load on the internal
components (cpu, memory etc..) that it is causing high frequencies to be generated which are pick-up by the
speakers. I have never seen this in Windows.

Just my input...