While playing around online I came across a forum and someone had asked what the little circle is that sometimes sits next to your signal bars. Apparently it indicates when you are in a GPRS network, which normally happens when you’re switching networks. I’m assuming it may be the same on both first and second gen iPhones, but I’m not sure. I always notice it when I’m on the train. Right before I enter NYC I lose Edge for a minute or two and I have that little circle. At least now I know what it stands for. Not sure, but it might have been at the MacRumors forum.