Been on US Cellular since May of 1998. With straight talk just changing policy and allowing a port over of phones I went out and picked up a used Captivate. It's a similar phone to Mesmerize(galaxy s) except for the 16gb of internal vs my 2gb on my current phone. I've started doing some reading and plan to ROM this phone(currently running CM7 on my Mesmerize). Never had GSM phone before. I'm sure these questions have been asked but I'm a year+ behind on this phone already so I've got a lot of reading and catching up to do. The only real burning question I have is will the ROM have any affect on the SIM card? It appears I'll have to manually setup the phones APN for voice/texting. I'm assuming with each rom I try until I find the one I like I'll be re-entering that data? Is there anything I really need to be careful of that could screw up the SIM card? I probably won't be up and running with the new service for a week or so. Am I better off picking and installing my ROM now then activating the phone on the new service or should I wait and it get it up and running first?