How do you activate an imported cell phone?

I live the U.S., but I want to import a phone from Korea. I currently have a Samsung Katana, and my network provider is Sprint. My phone doesn't have a removable SIM card, so I was wondering if when I buy the new phone, should I bring it to my provider and have them swap over the phone numbers, or what?

Thanks!

porting the number means moving your phone number to another carrier.tell them to do an esn swap.esn is your electronic serial number.its 8-22 digits on the back of your phone under the battery and will say esn and/or dec followed by the number.you dont have to go to the store you can actually call cust service and have them do it.make sure when you call your not on the cell phone thats going to be deactivated.you should call from a land line.and by the way there is no charge for doing this.

if the phone is cdma, and works on the 800-1900mhz it will work on sprint. yes, take it to sprint, and tell them to port the number.