1. Will I be able to update the firmware using NSU in India?

There is global Firmware which you can flash it with..NSU does not work yet...but updating via wifi OTA is supported i guess..!!

2. If something goes wrong with the phone what are my options other than returning it to Nokia Finland? Will Nokia India fix the phone with some charges or it won't be able to do that?

The phone is not officially launched in India, hence repairing at official Nokia Service is Impossible, because they will not be trained to handle the phone and will not stock the spares.

3. I suppose the phone will have English language support. Please comment

Obv it will have English language apart from the Nordic and other Languages

4. I noticed that the device was out of stock from Nokia Finland Store. Is the device available at retail outlets or it is only available at Nokia Stores?

I bought mine from newegg.com as nokia usa would not authorize my pals card

5. How much does Nokia usually takes to deliver the phone if booked on the internet?

Express shipment on nokia said 1-2 business days

6. Will it work on BSNL 3G. The frequency is 2100 MHz.

Thats what others have said, I dont have 3G at my home or workplace, hence not been tried by me but EDGE works fine..

7. Is there anything that I may miss out other than Nokia India warranty by purchasing N900 from Finland?

Nope...nothing...the phone runs like its supposed to..infact you will gain the respect of your friends, and obv their envy

8. What other points must I keep in mind and convey to my relative in Finland before purchasing the device?

Nothing really, preferably if your relative can get the box mannuals etc, then the resale value of the device is greater, but problems at customs might take place...barring that there is no issue,

Ive had my phone for a week on AirTel in kolkata, edge settings was dettected out of box and ive had no problems, no mic issue, no continuous reboots, batter is iffy because of pluings installed, but thats a software thing that can be fixed by flashing the device..congrats on your new purchase though