Trackpad Button Squeaking

I doubt it's a widespread issue.

It's possible that some sort of debris may be getting in the way of the button. I recommend making a genius bar appointment with your local Apple Store (or visiting an Apple-authorized service provider) and seeing about what one of the technicians can do for you (possibly clean, maybe replace). If the system is under warranty, I don't imagine you having any issues with getting the issue resolved. Unfortunately, aside from blasting the sides of the trackpad with compressed air, there isn't much that you yourself can/should do.

Hope this helps,
Brian

For well-known defects, I always check the AppleDefects wiki. That trackpad button is covered, but only barely. As previous poster suggested, it's probably not a wide-spread issue. Here you go:

http://www.appledefects.com/wiki/index.php?title=MacBook#Badtrackpadbutton