Right then, i just noticed that my Original MBA 1.6 80 gig, was making a different high pitched squeak to the usual hard drive one, it was going on and off and i couldn't figure out what it was, it seems to come from under the left side of the keyboard. I then realised that it only occurs if i put my finger on the trackpad! If i scroll or click and drag it stops, but if i just have my finger on the trackpad or move the cursor around normally there it is!!! It is very quiet and high pitched so you might not notice it until you are in a very quiet place! Just thought i would share this very strange find with you, anyone else notice this?