New MacBook Overheating Issue

I have a relatively new unibody MacBook.

I have just noticed tonight that when I was charging the MacBook, the upper left area of the computer (both on the top and bottom) is getting very hot - almost to the point that the bottom of the MacBook is too hot to touch. This occurs with no applications or processes running

I am fairly sure this has only started happening tonight. I am actually concerned that it is going to mark my wooden desk, as I am starting to smell a burning wood smell

I will be calling Apple to discuss tomorrow.

Has anyone else encountered a similar issue when they charge their MacBook?

UPDATE: After I restarted the MacBook, everything seems to OK now. Maybe there was some background process that was running, which was taxing the system. I should have checked before I did the restart. It is still a bit of a concern that it got so hot. I am glad that I noticed it before I went to bed.