I have a 32 GIG iphone 3gs. In the last month I have dropped more than 50% of my calls. I live in and work in Center City Philadelphia. I have returned my original 3gs to apple for a new phone, problem is still here. Restored from backup and setup the phone as new, still have the problem. Replaced Sim Card at ATT - same problem still exists. ATT Said to switch it to EDGE and I will not lose or drop calls. CAN THIS BE RIGHT? I cannot use 3gs on my phone? I have used 3g on the last iphone and it always worked ok. What should I do? Should I swap the phone out at Apple again? CRAZY!!!!!!!!