You can’t replace the battery; you will have to take the whole works to an Apple center where the asking price for a new battery is nearly $90 equivalent. The device is an iPod built into a phone, great sound & picture included - but with the corollary that you have to embrace Apple’s proprietary iTunes format.
1. No voice dialling.
2. No video recording.
3. No phone-to-phone photo sending (at least not easily)
4. A fairly ordinary camera with no zoom or flash.
5. No additional memory card slot (!).
One thing will hamper everyone, for now: until 3G speeds are offered in India, using the iPhone will be like buying a F1 racer to do your daily office commute. But at the inaugural price of Rs. 31,000/Rs 36,100 for the 8/16 GB respectively versions in India potential buyers are going to flaunt their phones; not necessarily use them to full functionality.
(The phone will only unlock with the service provider’s SIM card which is installed. Currently the choice is between Airtel & Vodafone.)