I had a battery drain issue on my iphone 3G. Then i google around and realise that safari is the culprit, because it say that it is in a loop that drain the battery, that was before 3.1. That time was 3.01. So what they basically tell is to reset the whole iphone as in restart it again not deleting everything.

So if you got battery drain issue and you feel your iphone very hot. Try holding down the home button and the standby button for it to be off and reset all the app from the loop. Wala, after that battery ok already. Back to normal.

Just my own experience