ok so i just got my iphone 3g today, and have been using the WiFi inside my house since that is the fastest. Now i decided to shut off WiFi and see how fast the 3g is. So i turn off WiFi and now im on EDGE WHY AM I ON EGDE!!!! i am on the south side of Chicago. 3g Service is dark blue here! Now i keep on switching back and forth between 3g and EDGE. What gives?