I made a video of it:
YouTube - High-Pitched Sound After OS X 10.5.7 Update on Macbook Pro

Noticed a high-pitched squealing sound after updating to OS X 10.5.7. I am using a 17" Unibody Macbook Pro.

During this recording using Garageband, I was also using Handbrake and Safari. Never had this problem before during the use of CPU-intensive programs. It also happens while scrolling a webpage in Safari and Safari being the only open application, but the sound is just a little lower.

-Sound is not originating from speakers, but from inside the machine.
-Volume of video was raised for clarity