Involves using a CDMA esn to make a new account, getting a new number, paying the money to activate the account.
Calling back and telling them that you want to migrate from your old phone to a new phone and telling them it is a boost motorola krzr and giving them the esn of the bb and following the instructions they give you. Also after everything is complete find service books to get the browser and mms to work. Took me about 10 minutes from start to finish although I did have to wait for data to provision which took a few hours.
So i just switched mine, works pretty good, internet is pretty fast too, not that different from actual sprint's. I just called them and told them i'm switching to krzr like mentioned above, and no problems. Transfered over servise book for mms and browser and it works. Hope this helps