i just notice when i'm at home, i only use wifi, so i disable 3G but the edge symbol is still appear, i don't need it and i just found out the setting to turn it off totally. i didn't realize that the setting is there. is it iOS4 only? my iPhone 4 has a better battery life than before, i can touch 7-7.30 hours of quite heavy usage including playing 3D games like gangstar and assasin creed. it can reach to 8.5-9hours without playing 3d games but heavy use on youtube, browsing and listening to music. my setting is brightness 60% with auto brightness turned on, 3G off, cellular data off, wifi on, location service on, notification on, mail set to fetch hourly.