Apple support..impressed for the first time!
I have a macbook bought exactly one year ago today, which has been perfetly OK apart from the slight mooing sound which comes and goes, and is only noticeable when im using it in a totally silent room anyway.
Last week though, I started to notice discoloration on the palm rests..just like I had read about last july (google for it :) )
Apple then officialy recognised the problem (after initially saying it was the users fault for being dirty!) and offered to replace the plastics on the affected models. Now I didnt think mine was affected (it was fine all year) until I noticed it last week..it annoyed me but I figured it was too late. Just phoned apple and they will replace the entire plastics of my macbook for me! Just have to take it to a store, and I have one 10 mins away so thats no problem..so pretty pleased, a shiny new set of plastics a year into owning one, go apple =)