Thursday, September 9, 2010 1:06 AM
This trick works for any iPhone running the new iOS 4.1 firmware.
Dial *3001#12345#* from your iPhone and watch the signal bars being replaced by a number. The lower the number, the better the signal. Hit the Home button to see the bars again.
If you have tried this trick, then please let us know how your signal is in the comments section below.