Like some of you I was having my 3GS battery drain much faster than my 3G. I took the phone to the Apple store and they checked something and swapped my phone for a new one. I charged the new phone up overnight. Battery seemed "a little better" Was using it some and by chance went into the usage menu and this was displayed: "Time since last full charge" Usage - Stand by - it shows no time, just a dash in each spot. The 1st 3GS phone that I swapped did that too. I was also getting calls, but the front caller ID screen was intermittently black, so I'd have to hit the home button to bring up the screen so I could answer the phone. It was odd that the 2nd phone had same 3 issues as first phone. Being in electronics, the chances of exact same problem in 2 devices that are pretty slim. Here is what I found out (in plain English) after speaking to Apple tech on the phone: They are finding out that sometimes if you set your new 3GS phone up from the back up from a 3G phone; something is fouling up the new phone. He had me restore, then set up the 3GS as a new phone. Took a bit to do, but not bad. I now have "Time since last full charge" usage & stand by readings - the battery meter stayed on full all last night, and I used it quite a bit. Before, it would have been around 70 - 80%. All calls have had caller ID working. Those of you having issues my want to try this. So far it has seemed to work for me. Hope it does for you too!