I've had a small dark circle on my screen for a few days now, and although it doesn't really interfere with what I am doing, it is rather annoying on a $300 iPod that is 2-3 months old. I tried pixel checker from the iSpazio repo and I ran it for a few minutes but it didn't do anything. The circle is about 5mm diameter and the edges make it look like it is a shadow. Also, it is black and not very opaque. Any idea what it could be, and how I might fix it?