Flexing Nokia N80 with Cingular firmware

Hey guys. I am getting ready to buy an unlocked phone, a Nokia N80. What is involved in making sure I can get on the internet, send picture messages, etc. I have read I need to get the phone "flexed" with Cingulars firmware? Is this something that can be done easily? Is it based on the phone you get or just generic for any phone? I want to be 100% sure this will work before I spedn $500 on this phone. Any help would be much appreciated.

Thanks.
Chris