i am thinking of purchasing an unlocked iphone and wondered because the sim cards are different in an iphone than a blackberry, would I be able to have a small sim card as well as the blackberry sim card?
You can buy another SIM Card to fit the iPhone then keep the old SIM Card that fits in your present phone & you can switch back and forth but only one will work at a time. You can just switch which ones active through self serve. Keep in mind that you have to activate each card withing 90 days to keep that card able to be activated at all. So just every couple months activate then deactivate the card your not using to keep it able to be activated.
Or you can cut the larger one to size & keep the outer shell you cut out so when you need to put it back into a device that uses a larger SIM just pop it back into the shell.
That's what I do - I have a single SIM with 2 shells so it fits nano, micro & standard SIM slots.