Currently Being ModeratedSep 28, 2013 6:18 PM (in response to yoshi15789)
Not clear what you mean by "original" iPhone 4, but the CDMA model cannot use SIM cards. The GSM models require SIM cards, of course.
If you mean changing the SIM card to another carrier in a carrier locked GSM iPhone 4, you need to contact the original carrier to get it unlocked.
Message was edited by: modular747