OK, when wifi is on and there is a connection, the iPhone uses wifi instead of 3G. I notice that when the phone comes out of standby, it is on 3G until it figures out wifi is on and connects (have confirmed this with my router - when asleep, no wifi connection, obviously). So, if wifi is on and the 3GS is asleep, then what pings email or anything else that may be "live"? 3G or wifi? 3G I suspect, right? Also - in general, when in wifi range, wifi is easier on the battery than pure 3G? I have 4-5 bars of 3G most of the time and average about 600 kbps overall (low of 200, high of 1800 depending on the time of day).