Hey i had this happen to me. flip the airplane mode toggle back and forth should get your service restored. I was concerned so i did a wipe and restored to 3.0 normal. However checking my account yesterday there was a service bulleten for my area of signal issues so maybe that is it or maybe not. Try the airplane trick if that works then maybe it is just temp. If you want to feel better just use the old nuke option and start over. These things can be very delicate none of what has been done should have caused issues but who knows what you iphone has installed setting etc to many variables to count. give those two things a shot if your still having issues ring up att.