Samsung has already launched a battery bundle kit for their Galaxy Nexus smartphone in the US market.
The kit comes with a 2100 mAh extended battery and a back cover that would be required after inserting this battery into the phone.
It is priced at USD 50 and is on sale right now.
Samsung Galaxy Nexus has just gone on sale in the US market through Verizon Wireless. We are waiting for it to arrive here in India.