Smartphone talk-times tested
The top performer in battery life was the Motorola DROID 2, at 465 minutes of talk-time. The DROID 2, however, also had the most inaccurately optimistic reported talk-time (575). The iPhone 4 had the next most disparate times, with 382 minutes of real time versus 420 reported.
The Samsung Captivate, HTC DROID Incredible, Palm Pre Plus, and iPhone 3GS all lasted about as long as their claims. The Samsung Captivate actually outperformed its estimate by 4 minutes. Yes, it's only 4 minutes, but we have to appreciate their modesty.
The phones were tested from the same location with music played throughout the calls (to simulate a conversation's battery drain), with Wi-Fi connected but Bluetooth disconnected.
source: Tested via Gizmodo