I have actually noticed the reverse. I live in an area right on the edge (no pun intended) of a 3G area, so my signal has never been stellar at home. However, where it used to be 1-2 bars, now the phone will frequently drop to "Searching..." for 30 or 40 seconds, before coming up with "No Service." Sometimes, even when I switch to Edge only, it still occurs, though not as often. Strangely, rebooting (or sometimes just going to airplane mode) will "fix" the signal. I could have "No Service", and, without moving, shut the phone off, turn it back on, and see 3 bars. Not sure if it is Apple problem or an AT&T problem, but my iPhone experience has definitely taken a sharp turn for the worse in the past month.